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With the holidays coming up, Bennett Haselton has updated his geek-oriented gift guide for 2014. He says: Some of my favorite gifts to give are still the ones that were listed in several different previously written posts, while a few new cool gift ideas emerged in 2014. Here are all my current best recommendations, listed in one place. Read on for the list, or to share any suggestions of your own.

Most annual gift guides would only list new items. It would be considered a mortal sin of click-baiting to tell the reader, "Well, the coolest stuff we could tell you about, was stuff that we mentioned this time last year, so first and foremost we're just going to direct you to that."

Well, my job in writing a gift guide is not to dazzle people with "all new hottest gift item" recommendations, my job is to recommend the things that I think you would most enjoy giving and the recipient would most enjoy receiving, and the fact of the matter is that most of the gifts I would most highly recommend, were listed in different previously written articles. I'll provide that list in a second (with links back to the older articles describing them in more detail), but first some criteria for how I make the recommendations.

First, I'm assuming you want to go inexpensive. If you have unlimited cash, you don't need my help finding cool presents -- although for the record, the online store of New York's Museum of Modern Art has the best collection of things that incorporate "visual puns" that I really like, but which are usually overpriced for what the item does. (Check out this image of a set of nesting tables, for example -- which isn't even that much of a "neat idea", by their standards -- and try to guess how much they cost, before looking at the answer on the product page.) If you don't mind spending the money, they also sell a dandelion encased in acrylic ($375), a lamp in the shape of an open book ($190), a necklace of small rectangular mirrors creating an interesting 3D effect ($190), a porcelain vase that kind of looks like a crinkled paper bag ($120), a pair of candleholders that interlock without touching ($170), a serving tray that looks like the splash from a drop of water ($130), a clock that evokes an M.C. Escher "infinite staircase" optical illusion ($80), and a vase that exists in the shape of an outline ($65, which at this point sounds cheap). At the end of this gift guide I list some MoMA items that are somewhat more reasonably priced.

Second, I'm assuming you don't need help finding branded merchandise. I'm sure literally every combination of [Star Wars / LOTR / Game of Thrones / Star Trek / Hunger Games] and [coffee mug / beach towel / earrings / Christmas tree ornaments / shot glass / cufflinks] is available somewhere. It's not that these are bad gifts for the hardcore fan, it's that all you need to find them is to Google "Game of Thrones Christmas tree ornaments" and you'll find something. And occasionally you'll will find something in this "branded" category that jumps out as a pretty cool idea, like the TARDIS Tea Infuser or the Game of Thrones Dragonclaw Goblet or the light-up lightsaber chopsticks.

Third, I look mostly for novelty or decorative items that confound your senses or demonstrate some interesting scientific principle (or both), but that can still fit in to a semi-elegant environment without garishly calling attention to themselves. These color changing beads are kind of neat, but it would look weird having them lying around on top of a living room dresser along with a UV flashlight to demonstrate what they do. On the other hand, a Galileo thermometer can blend in pretty well the decorations on a mantlepiece.

The following are my current most-recommended gift ideas:

Custom Photomosaic

In this December 2013 post I described how to create a photomosaic (a patchwork of smaller pictures that, when viewed from a distance, take on the appearance of a larger picture) using two free (donation-supported) programs, one to download and save pictures en masse from a friend's Facebook profile, and the other to create the photomosaic using those photos. I still think they make amazing gifts, and the only cost is the cost of printing and framing it. You can even give the digital-only version as a gift that costs nothing at all, making a photomosaic from a friend's photos and sending it to them on the other side of the world, where they can print it themselves or use it as a desktop background. Everyone that I've given one of these to, has loved it.

Strandbeest kit

With this $35 kit, which I recommended as a Christmas gift last year, you can assemble a tabletop version of the legendary full-size Strandbeests, the eerily lifelike creatures created by Dutch artist Theo Jansen which walk across the beaches of Holland powered only by the wind. Assembly of the creature takes about 90 minutes, less if you make a family activity out of it and share the labor.

In the last year, a second model has been released, dubbed the "Rhinoceros Mini-Beest (technically, it was available a year ago, but the assembly instructions were only printed in Japanese; now it's available with English directions). I haven't assembled one of these myself yet, but it looks fine in the video.

There is also now a pre-assembled, motorized, remote-control version of the Strandbeest, although honestly, where's the fun in that? Part of the effect of the Strandbeest assembly kit is the feeling that you've breathed life into an inanimate object by putting it together from static parts. A remote-control toy that moves forwards and backwards on the ground is a little underwhelming when you can get an RC helicopter for the same price.

Levitron Revolution and Levitron Cherrywood

The Levitron Revolution ($70) consists of a circular magnetic disc that levitates about half an inch above an electrically powered square base, and can support up to a pound of weight on top of it while maintaining levitation. The Levitron Cherrywood ($35) consists of a top that has to be spun by hand, which levitates almost a full two inches above the cherrywood base containing an embedded magnet. As described in the first gift guide, the Levitron Cherrywood is more visually impressive because of the extra height of levitation, but the top almost always falls if you touch the top or move the base while the top is spinning. The Levitron Revolution only levitates the disc by half an inch, but you can embellish the appearance by placing other objects on top of it, like the pyrite crystal levitating in this video. (Also, the Levitron Revolution will continue levitating as long as power is supplied to it, making it a good decorative item; the Levitron Cherrywood has to be spun by hand and levitates for only about two minutes before air friction slows it down, so it works better as a toy or party activity.) Both of them take some practice to operate (the Levitron Cherrywood takes considerably more), but they're worth it.

Spare batteries for your friend's phone

I mentioned this in January 2013 as a life hack for smartphones and got pilloried for promoting what people called an "obvious" idea. But two years later, almost nobody that I know is carrying around fully charged extra batteries for their phones. It's easy, it works, and the spare batteries in my jacket pockets have gotten me out of a jam multiple times. If you know what type of phone your gift recipient uses, get them some extra batteries. (T-Mobile sent me extra batteries for my LG Optimus for free.)

The iPhone is the only phone I'm aware of that does not support this, because the battery is not meant to be removed or replaced by the user.

And yes, I know about the portable external battery products that can be used to charge a phone. These aren't as big or expensive as they used to be, but you still have to leave them plugged in to your phone while they're charging it, which is awkward if you're using your phone or carrying it in your pocket (compared to the 10 seconds it takes to swap out the battery).

Heat Wave car heater

This $40 device from Canadian company "Heat & Clean" sits on your dashboard and turns itself on at a pre-determined time, blowing hot air into the interior of the car for 20 minutes, all without starting the car. If all goes well, this means your car will be warm (or at least not as cold as it would have been) when you first get into it in the morning, and you don't have to wait several minutes for the air ventilation system to heat up. The Heat Wave is powered by the car's 12V charger, although Heat & Clean states that "has built-in circuitry to ensure that the health of the vehicle's battery is never compromised."

I can't vouch for the device's respect for your battery (the device unfortunately isn't sold on Amazon, which is usually where I go to find out if something does what it's supposed to), but I ordered one and verified that it works, then gave it to my aunt for her birthday. (If it kills her car, I will promptly make it up to her by taking it out of the gift guide.) Even though I tested the functionality, I didn't get the chance to see if the device actually helps much, because it's not cold enough yet here in Seattle to really feel the bite of the cold when you get into your car in the morning. (The other reason I personally won't get much benefit from this, is that I work from home and leave the house at a different time every day, so I never know in advance what time I'll be getting into my car the next morning.)

Most cars can be modified so they can be started remotely, so that they're warmed up by the time you go outside and get into them, but that modification usually costs a few hundred dollars. You might as well try the Heat Wave first to see if it does the job almost as well.

(To me, the obvious question is: Why not make a version of the Heat Wave that can be turned remotely, as well? For people like me who usually don't know the night before what time they'll be getting into their car the next day, but who often do know at least 20 minutes in advance, so they can turn it on remotely and start heating the car. The company does make a very different-looking product called the Heat Stick which can be activated remotely -- but at $300, that's more than it costs to add remote start to the actual car.)

It's Nuts 3D puzzle

Distributed by Grand Illusions in the UK, the It's Nuts 3D puzzle consists of a bolt and a pair of nuts threaded onto the bolt. As you can see in the video, when you rotate one nut, it moves in the direction that you'd expect, following the threading on the bolt -- but when you rotate the other nut the same way, it moves in the opposite direction. There are no hidden moving parts to make the illusion work, and you can unscrew both nuts right off of the bolt and examine them.

Having acquired one, I can say that the secret is a little bit easier to figure out when you're holding it in your hand and looking at it closely, than when you're watching the video. But it still makes a nice novelty conversation piece.

As a brain-tickler, this feels a bit overpriced at $40 - costing more than the aforementioned Levitron Cherrywood, which actually levitates. I bought It's Nuts mainly to fill out my collection off oddities since I already owned most of the other items in this list. Of course, unlike the Levitron, this takes no skill to operate (only a little bit of smarts to figure out the secret). I wouldn't foist the Levitron on my grandfather, but he would probably enjoy this one.

(Note that if you buy from the Grand Illusions website to ship to the United States, you'll pay the non-VAT rate -- but then you'll have to add about $14 in air mail shipping to the U.S. So you might want to combine this order with some other items from Grand Illusions -- search this article for "Grand Illusions" for the other recommended items, or browse their site and pick your own.)

Inverter Magnet

The Inverter Magnet, from Grand Illusions (also available from Amazon at a slightly higher price), consists of one disc magnet encased in rubber, which holds a second disc magnet in a permanent "force field" a few millimeters away when the two are slid across a table.

At $40, this might be more of a "collection filler-outer", since especially as a magnetic toy it compares unfavorably with the Levitron Cherrywood, which, to repeat, can actually fly. But again, the Inverter Magnet also takes no skill to operate.

Magna Nails

This nail polish (about $7 used on Amazon) forms a stripe pattern when you hold a magnet near your fingernail while the polish is trying. (There are many similar products on the market, searchable under "magnetic nail polish.") The appeal to young science geeks is that the iron filings in the nail polish align themselves along magnetic field lines in the vicinity of the magnet, forming the stripes.

I don't wear glittery nail polish (at least not as "Bennett Haselton"...), but I took one for the team to see if this works. It does. That's my thumb. (Apparently it looks better if you apply a "top coat" after the nail polish dries, but I didn't have any.) If you plan on testing it out before giving it as a gift, remember to pick up some nail polish remover to get it off.

A few things from MoMA that we can actually afford

• An appetizer serving dish complete with toothpick holder that looks like a porcupine ($28). This item probably has the highest price-to-cool-factor ratio of anything on this list, just barely within the limit of what I'd recommend, but it's elegant in addition to being funny, and the recipient would probably use it.
• A faux-wood cube clock ($38). This is interesting mostly for looking like a visual impossibility -- how can the digital numbers appear on the side of a block of wood, even fake wood? Unfortunately I think the photo is doctored, because this youtube video shows an undoctored shot of the cube clock, and you can easily see the un-illuminated LEDs on the side, which don't quite blend in with the wood. But it still makes for an elegant optical illusion.

Miscellaneous "Visual Puns"

• The ambiguous vase ($33) from Grand Illusions -- a real-life version of the Rubin vase optical illusion, where a vase suddenly takes on the appearance of two faces in profile.
• The glass water faucet ($50)
• The sliced grandfather clock ($36)
• Ulexite "television stones" ($10) - a rock that, when placed on a flat surface, will cause the markings on that surface to re-appear on the top face of the rock, due to the naturally occurring fiber optics in ulexite.

Of course, if you're now craving one of these items for yourself, order one and try it out before re-gifting, or set up an Amazon wish list in the last two weeks before Christmas. And remember to be good!

With the holidays coming up, Bennett Haselton has updated his geek-oriented gift guide for 2014. He says: Some of my favorite gifts to give are still the ones that were listed in several different previously written posts, while a few new cool gift ideas emerged in 2014. Here are all my current best recommendations, listed in one place. Read on for the list, or to share any suggestions of your own.

Most annual gift guides would only list new items. It would be considered a mortal sin of click-baiting to tell the reader, "Well, the coolest stuff we could tell you about, was stuff that we mentioned this time last year, so first and foremost we're just going to direct you to that."

Well, my job in writing a gift guide is not to dazzle people with "all new hottest gift item" recommendations, my job is to recommend the things that I think you would most enjoy giving and the recipient would most enjoy receiving, and the fact of the matter is that most of the gifts I would most highly recommend, were listed in different previously written articles. I'll provide that list in a second (with links back to the older articles describing them in more detail), but first some criteria for how I make the recommendations.

First, I'm assuming you want to go inexpensive. If you have unlimited cash, you don't need my help finding cool presents -- although for the record, the online store of New York's Museum of Modern Art has the best collection of things that incorporate "visual puns" that I really like, but which are usually overpriced for what the item does. (Check out this image of a set of nesting tables, for example -- which isn't even that much of a "neat idea", by their standards -- and try to guess how much they cost, before looking at the answer on the product page.) If you don't mind spending the money, they also sell a dandelion encased in acrylic ($375), a lamp in the shape of an open book ($190), a necklace of small rectangular mirrors creating an interesting 3D effect ($190), a porcelain vase that kind of looks like a crinkled paper bag ($120), a pair of candleholders that interlock without touching ($170), a serving tray that looks like the splash from a drop of water ($130), a clock that evokes an M.C. Escher "infinite staircase" optical illusion ($80), and a vase that exists in the shape of an outline ($65, which at this point sounds cheap). At the end of this gift guide I list some MoMA items that are somewhat more reasonably priced.

Second, I'm assuming you don't need help finding branded merchandise. I'm sure literally every combination of [Star Wars / LOTR / Game of Thrones / Star Trek / Hunger Games] and [coffee mug / beach towel / earrings / Christmas tree ornaments / shot glass / cufflinks] is available somewhere. It's not that these are bad gifts for the hardcore fan, it's that all you need to find them is to Google "Game of Thrones Christmas tree ornaments" and you'll find something. And occasionally you'll will find something in this "branded" category that jumps out as a pretty cool idea, like the TARDIS Tea Infuser or the Game of Thrones Dragonclaw Goblet or the light-up lightsaber chopsticks.

Third, I look mostly for novelty or decorative items that confound your senses or demonstrate some interesting scientific principle (or both), but that can still fit in to a semi-elegant environment without garishly calling attention to themselves. These color changing beads are kind of neat, but it would look weird having them lying around on top of a living room dresser along with a UV flashlight to demonstrate what they do. On the other hand, a Galileo thermometer can blend in pretty well the decorations on a mantlepiece.

The following are my current most-recommended gift ideas:

Custom Photomosaic

In this December 2013 post I described how to create a photomosaic (a patchwork of smaller pictures that, when viewed from a distance, take on the appearance of a larger picture) using two free (donation-supported) programs, one to download and save pictures en masse from a friend's Facebook profile, and the other to create the photomosaic using those photos. I still think they make amazing gifts, and the only cost is the cost of printing and framing it. You can even give the digital-only version as a gift that costs nothing at all, making a photomosaic from a friend's photos and sending it to them on the other side of the world, where they can print it themselves or use it as a desktop background. Everyone that I've given one of these to, has loved it.

Strandbeest kit

With this $35 kit, which I recommended as a Christmas gift last year, you can assemble a tabletop version of the legendary full-size Strandbeests, the eerily lifelike creatures created by Dutch artist Theo Jansen which walk across the beaches of Holland powered only by the wind. Assembly of the creature takes about 90 minutes, less if you make a family activity out of it and share the labor.

In the last year, a second model has been released, dubbed the "Rhinoceros Mini-Beest (technically, it was available a year ago, but the assembly instructions were only printed in Japanese; now it's available with English directions). I haven't assembled one of these myself yet, but it looks fine in the video.

There is also now a pre-assembled, motorized, remote-control version of the Strandbeest, although honestly, where's the fun in that? Part of the effect of the Strandbeest assembly kit is the feeling that you've breathed life into an inanimate object by putting it together from static parts. A remote-control toy that moves forwards and backwards on the ground is a little underwhelming when you can get an RC helicopter for the same price.

Levitron Revolution and Levitron Cherrywood

The Levitron Revolution ($70) consists of a circular magnetic disc that levitates about half an inch above an electrically powered square base, and can support up to a pound of weight on top of it while maintaining levitation. The Levitron Cherrywood ($35) consists of a top that has to be spun by hand, which levitates almost a full two inches above the cherrywood base containing an embedded magnet. As described in the first gift guide, the Levitron Cherrywood is more visually impressive because of the extra height of levitation, but the top almost always falls if you touch the top or move the base while the top is spinning. The Levitron Revolution only levitates the disc by half an inch, but you can embellish the appearance by placing other objects on top of it, like the pyrite crystal levitating in this video. (Also, the Levitron Revolution will continue levitating as long as power is supplied to it, making it a good decorative item; the Levitron Cherrywood has to be spun by hand and levitates for only about two minutes before air friction slows it down, so it works better as a toy or party activity.) Both of them take some practice to operate (the Levitron Cherrywood takes considerably more), but they're worth it.

Spare batteries for your friend's phone

I mentioned this in January 2013 as a life hack for smartphones and got pilloried for promoting what people called an "obvious" idea. But two years later, almost nobody that I know is carrying around fully charged extra batteries for their phones. It's easy, it works, and the spare batteries in my jacket pockets have gotten me out of a jam multiple times. If you know what type of phone your gift recipient uses, get them some extra batteries. (T-Mobile sent me extra batteries for my LG Optimus for free.)

The iPhone is the only phone I'm aware of that does not support this, because the battery is not meant to be removed or replaced by the user.

And yes, I know about the portable external battery products that can be used to charge a phone. These aren't as big or expensive as they used to be, but you still have to leave them plugged in to your phone while they're charging it, which is awkward if you're using your phone or carrying it in your pocket (compared to the 10 seconds it takes to swap out the battery).

Heat Wave car heater

This $40 device from Canadian company "Heat & Clean" sits on your dashboard and turns itself on at a pre-determined time, blowing hot air into the interior of the car for 20 minutes, all without starting the car. If all goes well, this means your car will be warm (or at least not as cold as it would have been) when you first get into it in the morning, and you don't have to wait several minutes for the air ventilation system to heat up. The Heat Wave is powered by the car's 12V charger, although Heat & Clean states that "has built-in circuitry to ensure that the health of the vehicle's battery is never compromised."

I can't vouch for the device's respect for your battery (the device unfortunately isn't sold on Amazon, which is usually where I go to find out if something does what it's supposed to), but I ordered one and verified that it works, then gave it to my aunt for her birthday. (If it kills her car, I will promptly make it up to her by taking it out of the gift guide.) Even though I tested the functionality, I didn't get the chance to see if the device actually helps much, because it's not cold enough yet here in Seattle to really feel the bite of the cold when you get into your car in the morning. (The other reason I personally won't get much benefit from this, is that I work from home and leave the house at a different time every day, so I never know in advance what time I'll be getting into my car the next morning.)

Most cars can be modified so they can be started remotely, so that they're warmed up by the time you go outside and get into them, but that modification usually costs a few hundred dollars. You might as well try the Heat Wave first to see if it does the job almost as well.

(To me, the obvious question is: Why not make a version of the Heat Wave that can be turned remotely, as well? For people like me who usually don't know the night before what time they'll be getting into their car the next day, but who often do know at least 20 minutes in advance, so they can turn it on remotely and start heating the car. The company does make a very different-looking product called the Heat Stick which can be activated remotely -- but at $300, that's more than it costs to add remote start to the actual car.)

It's Nuts 3D puzzle

Distributed by Grand Illusions in the UK, the It's Nuts 3D puzzle consists of a bolt and a pair of nuts threaded onto the bolt. As you can see in the video, when you rotate one nut, it moves in the direction that you'd expect, following the threading on the bolt -- but when you rotate the other nut the same way, it moves in the opposite direction. There are no hidden moving parts to make the illusion work, and you can unscrew both nuts right off of the bolt and examine them.

Having acquired one, I can say that the secret is a little bit easier to figure out when you're holding it in your hand and looking at it closely, than when you're watching the video. But it still makes a nice novelty conversation piece.

As a brain-tickler, this feels a bit overpriced at $40 - costing more than the aforementioned Levitron Cherrywood, which actually levitates. I bought It's Nuts mainly to fill out my collection off oddities since I already owned most of the other items in this list. Of course, unlike the Levitron, this takes no skill to operate (only a little bit of smarts to figure out the secret). I wouldn't foist the Levitron on my grandfather, but he would probably enjoy this one.

(Note that if you buy from the Grand Illusions website to ship to the United States, you'll pay the non-VAT rate -- but then you'll have to add about $14 in air mail shipping to the U.S. So you might want to combine this order with some other items from Grand Illusions -- search this article for "Grand Illusions" for the other recommended items, or browse their site and pick your own.)

Inverter Magnet

The Inverter Magnet, from Grand Illusions (also available from Amazon at a slightly higher price), consists of one disc magnet encased in rubber, which holds a second disc magnet in a permanent "force field" a few millimeters away when the two are slid across a table.

At $40, this might be more of a "collection filler-outer", since especially as a magnetic toy it compares unfavorably with the Levitron Cherrywood, which, to repeat, can actually fly. But again, the Inverter Magnet also takes no skill to operate.

Magna Nails

This nail polish (about $7 used on Amazon) forms a stripe pattern when you hold a magnet near your fingernail while the polish is trying. (There are many similar products on the market, searchable under "magnetic nail polish.") The appeal to young science geeks is that the iron filings in the nail polish align themselves along magnetic field lines in the vicinity of the magnet, forming the stripes.

I don't wear glittery nail polish (at least not as "Bennett Haselton"...), but I took one for the team to see if this works. It does. That's my thumb. (Apparently it looks better if you apply a "top coat" after the nail polish dries, but I didn't have any.) If you plan on testing it out before giving it as a gift, remember to pick up some nail polish remover to get it off.

A few things from MoMA that we can actually afford

• An appetizer serving dish complete with toothpick holder that looks like a porcupine ($28). This item probably has the highest price-to-cool-factor ratio of anything on this list, just barely within the limit of what I'd recommend, but it's elegant in addition to being funny, and the recipient would probably use it.
• A faux-wood cube clock ($38). This is interesting mostly for looking like a visual impossibility -- how can the digital numbers appear on the side of a block of wood, even fake wood? Unfortunately I think the photo is doctored, because this youtube video shows an undoctored shot of the cube clock, and you can easily see the un-illuminated LEDs on the side, which don't quite blend in with the wood. But it still makes for an elegant optical illusion.

Miscellaneous "Visual Puns"

• The ambiguous vase ($33) from Grand Illusions -- a real-life version of the Rubin vase optical illusion, where a vase suddenly takes on the appearance of two faces in profile.
• The glass water faucet ($50)
• The sliced grandfather clock ($36)
• Ulexite "television stones" ($10) - a rock that, when placed on a flat surface, will cause the markings on that surface to re-appear on the top face of the rock, due to the naturally occurring fiber optics in ulexite.

Of course, if you're now craving one of these items for yourself, order one and try it out before re-gifting, or set up an Amazon wish list in the last two weeks before Christmas. And remember to be good!

Frequent contributor Bennett Haselton writes this week with his favorite novelty science gift items for 2012. Levitation engines, puzzles, optical illusions brought to life, and all of the tips and tricks he's found for getting the products to work correctly. Decorative, whimsical, and not too expensive — except for the items that have earned it by being pretty amazing. Read on for the details, and be sure to mention other good possibilities (Just 14 shopping days left until Christmas) in the comments below.

You already know how to find all the latest iPad or iPhone accessories, or how to find all the licensed merchandise if your BFF is a fan of some specific franchise. The items in this list are things that most people wouldn't even think to look for, but that I thought seemed interesting once I found out that they existed.

I'm more of a science geek than a gadget geek, so this list is built around optical illusions, whimsy, conversation pieces that demonstrate some scientific principle, and a reasonable budget. (The "Swinging Sticks Kinetic Energy Sculpture" from ThinkGeek is a work of art, but at $225, the price is apparently set to extract as much as possible from all the people who have to have one after seeing it in Iron Man 2.)

Also, unless otherwise noted, I've actually tried everything listed here and verified that it actually works; there were some items that I really wanted to make work, but couldn't. The Double Sand Sculpture, for example, looks great (especially in colors other than that ugly orange), but in all three models that American Science & Surplus sent me — the original plus the two free replacements — air bubbles formed in the hourglasses after a few days, which blocked the sand grains from flowing through the apertures. I could also never get Educational Innovations' Color Changing Nail Polish to change color, even under a UV light. And I loved the look of the Tornado Fountain from Fascinations.com, but no matter how I calibrated it, the drain at the bottom made a squirting and scraping sound like the last dregs of water draining from a bathtub, which pretty much killed its potential as a "tranquil" conversation piece. (As far as I can tell, any tabletop water fountain that costs less than $100 is either too noisy or doesn't work, but I haven't given up looking.) Of course, if you can get any of those things to work, more power to you.

For most of these items I've included the tips and tricks that I've accumulated for getting the full effect out of the product, tips that in some cases would have saved me a lot of hassle if I'd known them when the product first arrived. So you get the full benefit of my impulsive early-September Christmas shopping.

Neither I nor Slashdot make any profit from these links (except some items are from ThinkGeek, which is a corporate cousin of Slashdot for a few more weeks — but I didn't know that when I was making this list, and besides, it's not like you can put together a geek gift guide without including some stuff from ThinkGeek anyway).

Here are some of the things I've found that look as cool in person as they do in their catalog photos, and actually work:

- - - - - - - - - - - - - - - - - - - -

Levitron Revolution
Made by Fascinations.com, $100 from Innovatoys.com.

I bought my first "Levitron"-branded product out of a Sky Mall catalog 15 years ago, assuming the picture of the levitating spinning top had to be a doctored photo, and half-set on proving that the product was a sham. I had spent enough time trying to levitate repelling magnets as a kid to conclude that it "couldn't be done," but I held out the faintest glimmer of hope that this might be the holy grail that I'd given up chasing about 10 years earlier. When the box arrived, I spent all evening and a sleepness night trying to get it working (the original product had to be calibrated and balanced very carefully, and you could waste a lot of time trying to make it work if the weights or alignments were slightly off), until just as the sun was coming up, I got the spinning top to levitate above the magnetic base for about four seconds before falling, and felt as if it had all been worth it. And the Levitron product line has come a long way since then, so you probably won't have to journey to the edge of your sanity to get this latest one working.

The Levitron Revolution is a levitation device which uses a base containing four computer-controlled magnets, and a magnetic disc that levitates about 1/2-inch above the base and can support a weight of up to 1 pound placed on top of it while continuing to levitate. It still takes a bit of practice to learn how to position the disc above the base to start the levitation, but the payoff is worth the effort. You can even rotate the base sideways and upside down, and the levitating disc will stay in the same position relative to the base while you turn it.

I used mine to levitate a crystal specimen that I got from a specialty gem store, which set me back about another $30, but I liked the way it glittered in the lights from the magnetic base. The rock was labeled "quartz / pyrite / sphalerite" at the store, and if you're looking for a similar rock to go with the Levitron Revolution, it looks like you can find one on Google Shopping for less than I paid for mine.

You can also use the Levitron Revolution for homemade illusions like levitating a cupcake in mid-air. (A Hostess dessert cup has a circular cavity on top to hold strawberries and whipped cream; turn it upside down and it fits perfectly over the Levitron disc. The book underneath the cupcake in the video was hollowed out to contain the magnetic base.)

Innovatoys sells several other Levitron products made by Fascinations, which all fall into two categories: those based on the classic Levitron design (which include any product showing the yellow-necked Levitron spinning top), and those based on the newer Levitron Revolution technology (everything else). I also have a Levitron CherryWood which is part of the "classic" lineup. The pros and cons of the two series are:

• The classic Levitron levitates the spinning top a full two inches above the base, which is much more visually impressive than the 1/2-inch that the magnetic disc floats above the base of the Levitron Revolution.
• The classic Levitron has to be hand-spun, however, and takes even more practice to operate than the Levitron Revolution.
• The classic Levitron has to be perfectly level for the top to float (the base comes with three adjustable legs to help you level it perfectly); the Levitron Revolution can be tilted and rotated, and the magnetic disc will continue to float in position relative to the base.
• The classic Levitron levitates in a very delicate equilibrium, with just the slightest touch being enough to push the floating top out out of balance and make it fall, so it can't be used to support other objects (and the top is spinning so fast that you wouldn't be able to see anything attached to it anyway). The Levitron Revolution floating disc can be touched and objects can be placed on top of it without pushing it out of equilibrium.
• The classic Levitron requires no power to operate, but because the top has to keep spinning at a high rate for the gyroscopic force to keep it from flipping over, after about two minutes the air friction will slow down the top enough that it falls. The Levitron Revolution will levitate forever as long as the DC power supply is connected.

The Levitron invention itself has something of a contentious history (recounted here and here). Evidently, the physicist Ray Harrigan had patented a similar device a few years earlier and showed it to Bill Hones, who later got his own patent for a similar device and called it the "Levitron," but Hones was advised by his own lawyer that his own invention was sufficiently different from Harrigan's that he could market it without infringing Harrigan's patent or giving him credit or royalties. Apparently Harrigan was so disgusted and distrustful of his own lawyer that he never took the issue to court, so we'll never know what a judge would have thought. (The only issue which was ever litigated in court was over a former re-seller's use of the trademark "Levitron" — but that seems more straightforward, since the company that made up the word and trademarked it, owns it, completely separate from the merits of the invention that bears the name.) Some physicists have mixed feelings about the Levitron because of this, but it was apparently Harrigan's choice not to pursue the issue. (Besides, the new Levitron Revolution design uses nothing of Harrigan's idea, so some might feel that it's less "tainted".)

For cheaper levitation that takes no skill to operate, you can get the Diamagnetic Levitation Kit from Educational Innovations or search for pyrolitic graphite levitation on eBay — much less visually impressive though, with the graphite sheet levitating only 1 millimeter above the magnets.

Or for a more expensive conversation piece, the Levitron Lamp ($450 from InnovaToys or $400 from WorldToHome) levitates an entire lampshade above the base. I haven't tried that one out though.

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Levitating Picture Frames
Heart-shaped frame $25 from ZOpid; rectangular frame $70 from Hammacher Schlemmer.

Computer-controlled levitation operating on a similar principle to the Levitron Revolution products. The $25 ZOpid picture frame is currently hanging out in Amazon limbo with a solitary 1-star review from a customer whose model broke after 4 months. But I think they look fine, and I'm giving two of them as gifts and crossing my fingers that I'm not that unlucky. With both the ZOpid and the Hammacher Schlemmer frames, unfortunately, there's apparently no way to switch off the LED lights (short of turning off the whole model).

Protip: You can prepare these as gifts by using photos downloaded from a friend's Facebook profile, but Facebook reduces the quality of uploaded photos, so that if you print them out, the pixellation will be noticeable up close. If you want the photos to look the best, you need to print them from high-res originals.

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Hanayama Japanese Pocket Puzzles
$13 from ThinkGeek and other vendors; some puzzles available for slightly less on eBay.

Some disassembly puzzles are complete fails, either because there are so many separately moving pieces that you can't manipulate the puzzles in your hands at all (e.g. Yin and Yang"), or the moving parts are hidden from view so you can only "solve" them by pure guesswork (e.g. the "Bolted Closed" puzzle). The Hanayama pocket puzzles actually get it right — you can see all the pieces and move them comfortably in your hands, so solving them is just a matter of figuring out the right sequence of moves.

These are basically grown-up versions of the twisted nail puzzles you might have grown up with (and which you could also get, of course, as much cheaper stocking stuffers). But the Hanayama ones look good as shelf knick-knacks as well.

Hanayama pocket puzzles come with no solution included, but you can download a solution by going to this page and submitting your email address to request a download link.

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LED Jellyfish Mood Lamp
$35 from ThinkGeek and other vendors; no cheaper alternatives on eBay

Works more or less as shown in the video, with one caveat: In both the first model that I tried, and the free replacement ThinkGeek sent me when I reported the problem, the transitions between the different colors were much more abrupt and jarring than the smooth "color fade" shown in the video. (For some reason, some color LEDs would switch from completely on to completely off at the same time that other LEDs would switch on.) Unfortunately this small problem completely breaks the "reverie" effect of staring at the jellyfish floating around in the water, so I just set mine to a single color without using the transition effect.

Protip: You have to use real distilled water like the instructions tell you. I tried to make it work with regular tap water, and bubbles kept forming around the jellyfish and causing them to float to the surface. Fill it with distilled water and the jellyfish should sink beneath the surface without too much trouble.

Note, Fascinations has come out with a similar product, again sold on Innovatoys.com; I haven't tried that one, so it might be better (might actually get the color transition right), or it might not. Discovery Kids also makes a similar product which I haven't seen and which has been pulling pretty bad reviews on Amazon.

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Vino Vault and Cryptex Puzzle Pod
$30 and $22 from 4Thought Products LLC

The Puzzle Pod is a gift container that can only be opened by arranging the 5 rings to spell out a 5-letter password. It arrives pre-configured with the keyword "GRAPE"; once opened, you can re-configure the Pod with a new 5-letter secret word, seal a gift inside, and gift it to a recipient who has to find the secret word to open the puzzle and retrieve the gift. (It's re-usable, and you can set a different 5-letter "password" every time.) The Vino Vault is a larger version of the Puzzle Pod that can hold a bottle of wine.

I've only sampled the Puzzle Pod, so I can just vouch for the fact that it works exactly as described and doesn't get stuck or break easily. When you line up the letters of the secret word correctly, it actually slides smoothly open like it's supposed to.

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Ambiguous Vase
$33 from Grand Illusions Ltd (ships from the UK)

This is a real-life version of the Rubin vase optical illusion. For years, Grand Illusions sold only a ceramic version for about $400 (plus another $200 to ship to the U.S.), but in November 2012 they released the $33 plastic version. It can also be used as a real vase (as long as you don't mind the barrier running down the center that divides the two halves).

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Steam Powered Top
$14 from Grand Illusions (ships from the UK)

The world's simplest steam engine, made from a tube of copper pushed through a piece of cork, as shown in the demo video. Wikipedia explains the principle here — when the water in the copper tube is heated by the candle flame and boils, it expands and pushes out the ends of the tubes (driving the spinning motion). When the water contracts again, in sucks in water through the ends of the tubes — but the sucking motion pulls in water from all directions (while the expulsion of water pushes in only one direction), so the suction doesn't counteract the propulsion, and the top continues spinning.

Now, the original version is from Germany (and comes with detailed German instructions); the version that I got came with a sheet of English instructions that weren't as detailed. The instructions say to push the copper tube through the cork platform and "bend the tube at a 90-degree angle"; however if you just try bending the tube, it will probably crimp and create a hole, making it useless. To bend the tube so that it curves gradually, place your thumb on the cork next to where the tube protrudes, and use the fingers of your other hand to gently push the tube so that curves around your thumb. (This is spelled out in the original German instructions.)

Also, the instructions say to fill the copper tube by holding it under running tap water. This didn't work at all for me, since the tube is only about 2mm wide and the surface tension of water makes it hard to "push" it into a tube that small. Fortunately, a straw from a grocery-store juicebox fits perfectly over the other end of the copper tube, so if you submerge the other end in water, you can suck on the straw to fill the tube that way. (It's just copper after all, not lead.)

Finally, if you leave the cork floating in water too long, it eventually gets waterlogged and sinks, and as far as I can tell it's very hard to dry it out and bring it back to its original buoyancy. The workarounds for this are: (1) to increase the buoyancy, first put another tea light directly into your bowl of water so that it floats, and then lower the top into the water on top of that tea light, which will then help keep the top afloat; and (2) don't leave the top floating in water when not in use.

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"Flying F*CK" Remote-Control Helicopter
$20 from ThinkGeek

Again with the ThinkGeek swag; I swear I didn't know.

This is pretty self-explanatory, except I've tried two of them and the product doesn't seem to work too well as an actual remote-control helicopter; one of them couldn't hover in place (its two modes were "shooting up at the ceiling" or "falling"), and with the other, the R/C didn't seem to work through furniture. But that's probably OK since the whole point of this gift is in the giving and not the having.

In my case, I hid it behind a friend's chair at his birthday party, then at the appropriate time gave a speech ending with, "And so I thought, what do I give my friend to mark this occasion? What do I give? After much thought, I decided, this is what I give:..." There followed a dramatic pause where I pressed the "up" control on the remote, and nothing happened, whereupon I muttered, appropriately enough, "Fuck", then wandered over behind my friend's chair, repeated the setup line, pressed the remote button, at which point the copter shot up, banged into a chair and fell to the ground, whereupon for my third attempt I just picked it up and held it on the palm of my hand, pressed the remote, and the copter took flight and finally delivered the punch line, and all was good. If I'm there when he re-gifts it (since we both agreed that was the point of a gift like this), I hope it works better for him.

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Falling Sand Sculptures
$13 for the smaller 'Sandscape'; $80 for the larger 'Deep Sea Round'; both available from Educational Innovations

These both make good decorations and shelf widgets. The sand in the Sandscape always falls in more or less the same pattern, since it's pre-determined by the gaps in the shelves holding the sand; the Deep Sea Round is more interesting since the pattern is determined by the placement of air bubbles and varies every time.

Pro tip: water evaporates from both of these, so eventually the water level will drop and the volume of air will increase, getting in the way of the sand flow. The 'Deep Sea Round' comes with a syringe that you can use to draw out air and inject more water into the aperture on the side. The cheaper 'Sandscape' doesn't come with a syringe, but it has a hole in the side where you can use a syringe to inject more water, if you buy the syringe separately.

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Galileo Thermometer
$17 for a wood-mounted model from Office Playground; cheaper ones available without wood mounting

Just your basic elegant conversation piece demonstrating the principle that the density of a liquid changes with temperature. Pro tip: If you get the wood mounted one, before emailing the seller to complain that it's not working because all the spheres are bunched together at the wrong end, make sure it's not upside-down. (I realized, before I hit Send, that the felt-covered end goes on the bottom.)

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All of the remaining items on this list do exactly what they say they do, with no need for any special instructions not included by the manufacturer, so I'm just going to list them:

Glass Water Faucet — $50 from Uncommon Goods — a nice double optical illusion (faucet suspended in space, and glass-as-water).

Slicked Grandfather Clock — $30-$60 depending on who's selling it.

Tin Can Robot Kit — about $15 from various vendors — my stepdad and I assembled one using one of his beloved Hansen's soda cans.

Mini metal DIY sculptures — the Metal Works sculptures from Innovatoys ($7-$12) take some time to assemble but they come out looking pretty much like the pictures and make good shelf decorations. These Mikro sculptures ($10 and up, also available from Grand Illusions if you're filling your shopping cart there) are a bit easier to assemble since you just have to bend some shapes out from the metal sheet that they're carved from.

Ulexite "Television Stones" — $10 from Educational Innovations — a naturally occuring rock containing thousands of parallel fiber optic strands. Give it as a gift together with a square of patterned fabric so you can see the eerie effect when you place the rock against the fabric and the pattern "magically" appears on the opposite side of the rock.

And finally, if you need a last-minute gag gift for someone, browse through the gum and hand sanitizers from BlueQ.com — they're not geek-themed, but at $5.49 for the hand sanitizers and $1.39 for the gum, you can afford to stock up so you'll have a reserve of gag gifts suited for a variety of different people's tastes (except, of course, good taste).

And those are my favorites for gift-giving season 2012. You can send me suggestions for any items in this category that I've missed; I'll be back for Valentine's Day.

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Remember, if you have a feature idea, we'd love to hear it.

Frequent contributor Bennett Haselton writes this week with his favorite novelty science gift items for 2012. Levitation engines, puzzles, optical illusions brought to life, and all of the tips and tricks he's found for getting the products to work correctly. Decorative, whimsical, and not too expensive — except for the items that have earned it by being pretty amazing. Read on for the details, and be sure to mention other good possibilities (Just 14 shopping days left until Christmas) in the comments below.

You already know how to find all the latest iPad or iPhone accessories, or how to find all the licensed merchandise if your BFF is a fan of some specific franchise. The items in this list are things that most people wouldn't even think to look for, but that I thought seemed interesting once I found out that they existed.

I'm more of a science geek than a gadget geek, so this list is built around optical illusions, whimsy, conversation pieces that demonstrate some scientific principle, and a reasonable budget. (The "Swinging Sticks Kinetic Energy Sculpture" from ThinkGeek is a work of art, but at $225, the price is apparently set to extract as much as possible from all the people who have to have one after seeing it in Iron Man 2.)

Also, unless otherwise noted, I've actually tried everything listed here and verified that it actually works; there were some items that I really wanted to make work, but couldn't. The Double Sand Sculpture, for example, looks great (especially in colors other than that ugly orange), but in all three models that American Science & Surplus sent me — the original plus the two free replacements — air bubbles formed in the hourglasses after a few days, which blocked the sand grains from flowing through the apertures. I could also never get Educational Innovations' Color Changing Nail Polish to change color, even under a UV light. And I loved the look of the Tornado Fountain from Fascinations.com, but no matter how I calibrated it, the drain at the bottom made a squirting and scraping sound like the last dregs of water draining from a bathtub, which pretty much killed its potential as a "tranquil" conversation piece. (As far as I can tell, any tabletop water fountain that costs less than $100 is either too noisy or doesn't work, but I haven't given up looking.) Of course, if you can get any of those things to work, more power to you.

For most of these items I've included the tips and tricks that I've accumulated for getting the full effect out of the product, tips that in some cases would have saved me a lot of hassle if I'd known them when the product first arrived. So you get the full benefit of my impulsive early-September Christmas shopping.

Neither I nor Slashdot make any profit from these links (except some items are from ThinkGeek, which is a corporate cousin of Slashdot for a few more weeks — but I didn't know that when I was making this list, and besides, it's not like you can put together a geek gift guide without including some stuff from ThinkGeek anyway).

Here are some of the things I've found that look as cool in person as they do in their catalog photos, and actually work:

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Levitron Revolution
Made by Fascinations.com, $100 from Innovatoys.com.

I bought my first "Levitron"-branded product out of a Sky Mall catalog 15 years ago, assuming the picture of the levitating spinning top had to be a doctored photo, and half-set on proving that the product was a sham. I had spent enough time trying to levitate repelling magnets as a kid to conclude that it "couldn't be done," but I held out the faintest glimmer of hope that this might be the holy grail that I'd given up chasing about 10 years earlier. When the box arrived, I spent all evening and a sleepness night trying to get it working (the original product had to be calibrated and balanced very carefully, and you could waste a lot of time trying to make it work if the weights or alignments were slightly off), until just as the sun was coming up, I got the spinning top to levitate above the magnetic base for about four seconds before falling, and felt as if it had all been worth it. And the Levitron product line has come a long way since then, so you probably won't have to journey to the edge of your sanity to get this latest one working.

The Levitron Revolution is a levitation device which uses a base containing four computer-controlled magnets, and a magnetic disc that levitates about 1/2-inch above the base and can support a weight of up to 1 pound placed on top of it while continuing to levitate. It still takes a bit of practice to learn how to position the disc above the base to start the levitation, but the payoff is worth the effort. You can even rotate the base sideways and upside down, and the levitating disc will stay in the same position relative to the base while you turn it.

I used mine to levitate a crystal specimen that I got from a specialty gem store, which set me back about another $30, but I liked the way it glittered in the lights from the magnetic base. The rock was labeled "quartz / pyrite / sphalerite" at the store, and if you're looking for a similar rock to go with the Levitron Revolution, it looks like you can find one on Google Shopping for less than I paid for mine.

You can also use the Levitron Revolution for homemade illusions like levitating a cupcake in mid-air. (A Hostess dessert cup has a circular cavity on top to hold strawberries and whipped cream; turn it upside down and it fits perfectly over the Levitron disc. The book underneath the cupcake in the video was hollowed out to contain the magnetic base.)

Innovatoys sells several other Levitron products made by Fascinations, which all fall into two categories: those based on the classic Levitron design (which include any product showing the yellow-necked Levitron spinning top), and those based on the newer Levitron Revolution technology (everything else). I also have a Levitron CherryWood which is part of the "classic" lineup. The pros and cons of the two series are:

• The classic Levitron levitates the spinning top a full two inches above the base, which is much more visually impressive than the 1/2-inch that the magnetic disc floats above the base of the Levitron Revolution.
• The classic Levitron has to be hand-spun, however, and takes even more practice to operate than the Levitron Revolution.
• The classic Levitron has to be perfectly level for the top to float (the base comes with three adjustable legs to help you level it perfectly); the Levitron Revolution can be tilted and rotated, and the magnetic disc will continue to float in position relative to the base.
• The classic Levitron levitates in a very delicate equilibrium, with just the slightest touch being enough to push the floating top out out of balance and make it fall, so it can't be used to support other objects (and the top is spinning so fast that you wouldn't be able to see anything attached to it anyway). The Levitron Revolution floating disc can be touched and objects can be placed on top of it without pushing it out of equilibrium.
• The classic Levitron requires no power to operate, but because the top has to keep spinning at a high rate for the gyroscopic force to keep it from flipping over, after about two minutes the air friction will slow down the top enough that it falls. The Levitron Revolution will levitate forever as long as the DC power supply is connected.

The Levitron invention itself has something of a contentious history (recounted here and here). Evidently, the physicist Ray Harrigan had patented a similar device a few years earlier and showed it to Bill Hones, who later got his own patent for a similar device and called it the "Levitron," but Hones was advised by his own lawyer that his own invention was sufficiently different from Harrigan's that he could market it without infringing Harrigan's patent or giving him credit or royalties. Apparently Harrigan was so disgusted and distrustful of his own lawyer that he never took the issue to court, so we'll never know what a judge would have thought. (The only issue which was ever litigated in court was over a former re-seller's use of the trademark "Levitron" — but that seems more straightforward, since the company that made up the word and trademarked it, owns it, completely separate from the merits of the invention that bears the name.) Some physicists have mixed feelings about the Levitron because of this, but it was apparently Harrigan's choice not to pursue the issue. (Besides, the new Levitron Revolution design uses nothing of Harrigan's idea, so some might feel that it's less "tainted".)

For cheaper levitation that takes no skill to operate, you can get the Diamagnetic Levitation Kit from Educational Innovations or search for pyrolitic graphite levitation on eBay — much less visually impressive though, with the graphite sheet levitating only 1 millimeter above the magnets.

Or for a more expensive conversation piece, the Levitron Lamp ($450 from InnovaToys or $400 from WorldToHome) levitates an entire lampshade above the base. I haven't tried that one out though.

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Levitating Picture Frames
Heart-shaped frame $25 from ZOpid; rectangular frame $70 from Hammacher Schlemmer.

Computer-controlled levitation operating on a similar principle to the Levitron Revolution products. The $25 ZOpid picture frame is currently hanging out in Amazon limbo with a solitary 1-star review from a customer whose model broke after 4 months. But I think they look fine, and I'm giving two of them as gifts and crossing my fingers that I'm not that unlucky. With both the ZOpid and the Hammacher Schlemmer frames, unfortunately, there's apparently no way to switch off the LED lights (short of turning off the whole model).

Protip: You can prepare these as gifts by using photos downloaded from a friend's Facebook profile, but Facebook reduces the quality of uploaded photos, so that if you print them out, the pixellation will be noticeable up close. If you want the photos to look the best, you need to print them from high-res originals.

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Hanayama Japanese Pocket Puzzles
$13 from ThinkGeek and other vendors; some puzzles available for slightly less on eBay.

Some disassembly puzzles are complete fails, either because there are so many separately moving pieces that you can't manipulate the puzzles in your hands at all (e.g. Yin and Yang"), or the moving parts are hidden from view so you can only "solve" them by pure guesswork (e.g. the "Bolted Closed" puzzle). The Hanayama pocket puzzles actually get it right — you can see all the pieces and move them comfortably in your hands, so solving them is just a matter of figuring out the right sequence of moves.

These are basically grown-up versions of the twisted nail puzzles you might have grown up with (and which you could also get, of course, as much cheaper stocking stuffers). But the Hanayama ones look good as shelf knick-knacks as well.

Hanayama pocket puzzles come with no solution included, but you can download a solution by going to this page and submitting your email address to request a download link.

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LED Jellyfish Mood Lamp
$35 from ThinkGeek and other vendors; no cheaper alternatives on eBay

Works more or less as shown in the video, with one caveat: In both the first model that I tried, and the free replacement ThinkGeek sent me when I reported the problem, the transitions between the different colors were much more abrupt and jarring than the smooth "color fade" shown in the video. (For some reason, some color LEDs would switch from completely on to completely off at the same time that other LEDs would switch on.) Unfortunately this small problem completely breaks the "reverie" effect of staring at the jellyfish floating around in the water, so I just set mine to a single color without using the transition effect.

Protip: You have to use real distilled water like the instructions tell you. I tried to make it work with regular tap water, and bubbles kept forming around the jellyfish and causing them to float to the surface. Fill it with distilled water and the jellyfish should sink beneath the surface without too much trouble.

Note, Fascinations has come out with a similar product, again sold on Innovatoys.com; I haven't tried that one, so it might be better (might actually get the color transition right), or it might not. Discovery Kids also makes a similar product which I haven't seen and which has been pulling pretty bad reviews on Amazon.

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Vino Vault and Cryptex Puzzle Pod
$30 and $22 from 4Thought Products LLC

The Puzzle Pod is a gift container that can only be opened by arranging the 5 rings to spell out a 5-letter password. It arrives pre-configured with the keyword "GRAPE"; once opened, you can re-configure the Pod with a new 5-letter secret word, seal a gift inside, and gift it to a recipient who has to find the secret word to open the puzzle and retrieve the gift. (It's re-usable, and you can set a different 5-letter "password" every time.) The Vino Vault is a larger version of the Puzzle Pod that can hold a bottle of wine.

I've only sampled the Puzzle Pod, so I can just vouch for the fact that it works exactly as described and doesn't get stuck or break easily. When you line up the letters of the secret word correctly, it actually slides smoothly open like it's supposed to.

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Ambiguous Vase
$33 from Grand Illusions Ltd (ships from the UK)

This is a real-life version of the Rubin vase optical illusion. For years, Grand Illusions sold only a ceramic version for about $400 (plus another $200 to ship to the U.S.), but in November 2012 they released the $33 plastic version. It can also be used as a real vase (as long as you don't mind the barrier running down the center that divides the two halves).

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Steam Powered Top
$14 from Grand Illusions (ships from the UK)

The world's simplest steam engine, made from a tube of copper pushed through a piece of cork, as shown in the demo video. Wikipedia explains the principle here — when the water in the copper tube is heated by the candle flame and boils, it expands and pushes out the ends of the tubes (driving the spinning motion). When the water contracts again, in sucks in water through the ends of the tubes — but the sucking motion pulls in water from all directions (while the expulsion of water pushes in only one direction), so the suction doesn't counteract the propulsion, and the top continues spinning.

Now, the original version is from Germany (and comes with detailed German instructions); the version that I got came with a sheet of English instructions that weren't as detailed. The instructions say to push the copper tube through the cork platform and "bend the tube at a 90-degree angle"; however if you just try bending the tube, it will probably crimp and create a hole, making it useless. To bend the tube so that it curves gradually, place your thumb on the cork next to where the tube protrudes, and use the fingers of your other hand to gently push the tube so that curves around your thumb. (This is spelled out in the original German instructions.)

Also, the instructions say to fill the copper tube by holding it under running tap water. This didn't work at all for me, since the tube is only about 2mm wide and the surface tension of water makes it hard to "push" it into a tube that small. Fortunately, a straw from a grocery-store juicebox fits perfectly over the other end of the copper tube, so if you submerge the other end in water, you can suck on the straw to fill the tube that way. (It's just copper after all, not lead.)

Finally, if you leave the cork floating in water too long, it eventually gets waterlogged and sinks, and as far as I can tell it's very hard to dry it out and bring it back to its original buoyancy. The workarounds for this are: (1) to increase the buoyancy, first put another tea light directly into your bowl of water so that it floats, and then lower the top into the water on top of that tea light, which will then help keep the top afloat; and (2) don't leave the top floating in water when not in use.

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"Flying F*CK" Remote-Control Helicopter
$20 from ThinkGeek

Again with the ThinkGeek swag; I swear I didn't know.

This is pretty self-explanatory, except I've tried two of them and the product doesn't seem to work too well as an actual remote-control helicopter; one of them couldn't hover in place (its two modes were "shooting up at the ceiling" or "falling"), and with the other, the R/C didn't seem to work through furniture. But that's probably OK since the whole point of this gift is in the giving and not the having.

In my case, I hid it behind a friend's chair at his birthday party, then at the appropriate time gave a speech ending with, "And so I thought, what do I give my friend to mark this occasion? What do I give? After much thought, I decided, this is what I give:..." There followed a dramatic pause where I pressed the "up" control on the remote, and nothing happened, whereupon I muttered, appropriately enough, "Fuck", then wandered over behind my friend's chair, repeated the setup line, pressed the remote button, at which point the copter shot up, banged into a chair and fell to the ground, whereupon for my third attempt I just picked it up and held it on the palm of my hand, pressed the remote, and the copter took flight and finally delivered the punch line, and all was good. If I'm there when he re-gifts it (since we both agreed that was the point of a gift like this), I hope it works better for him.

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Falling Sand Sculptures
$13 for the smaller 'Sandscape'; $80 for the larger 'Deep Sea Round'; both available from Educational Innovations

These both make good decorations and shelf widgets. The sand in the Sandscape always falls in more or less the same pattern, since it's pre-determined by the gaps in the shelves holding the sand; the Deep Sea Round is more interesting since the pattern is determined by the placement of air bubbles and varies every time.

Pro tip: water evaporates from both of these, so eventually the water level will drop and the volume of air will increase, getting in the way of the sand flow. The 'Deep Sea Round' comes with a syringe that you can use to draw out air and inject more water into the aperture on the side. The cheaper 'Sandscape' doesn't come with a syringe, but it has a hole in the side where you can use a syringe to inject more water, if you buy the syringe separately.

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Galileo Thermometer
$17 for a wood-mounted model from Office Playground; cheaper ones available without wood mounting

Just your basic elegant conversation piece demonstrating the principle that the density of a liquid changes with temperature. Pro tip: If you get the wood mounted one, before emailing the seller to complain that it's not working because all the spheres are bunched together at the wrong end, make sure it's not upside-down. (I realized, before I hit Send, that the felt-covered end goes on the bottom.)

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All of the remaining items on this list do exactly what they say they do, with no need for any special instructions not included by the manufacturer, so I'm just going to list them:

Glass Water Faucet — $50 from Uncommon Goods — a nice double optical illusion (faucet suspended in space, and glass-as-water).

Slicked Grandfather Clock — $30-$60 depending on who's selling it.

Tin Can Robot Kit — about $15 from various vendors — my stepdad and I assembled one using one of his beloved Hansen's soda cans.

Mini metal DIY sculptures — the Metal Works sculptures from Innovatoys ($7-$12) take some time to assemble but they come out looking pretty much like the pictures and make good shelf decorations. These Mikro sculptures ($10 and up, also available from Grand Illusions if you're filling your shopping cart there) are a bit easier to assemble since you just have to bend some shapes out from the metal sheet that they're carved from.

Ulexite "Television Stones" — $10 from Educational Innovations — a naturally occuring rock containing thousands of parallel fiber optic strands. Give it as a gift together with a square of patterned fabric so you can see the eerie effect when you place the rock against the fabric and the pattern "magically" appears on the opposite side of the rock.

And finally, if you need a last-minute gag gift for someone, browse through the gum and hand sanitizers from BlueQ.com — they're not geek-themed, but at $5.49 for the hand sanitizers and $1.39 for the gum, you can afford to stock up so you'll have a reserve of gag gifts suited for a variety of different people's tastes (except, of course, good taste).

And those are my favorites for gift-giving season 2012. You can send me suggestions for any items in this category that I've missed; I'll be back for Valentine's Day.

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Remember, if you have a feature idea, we'd love to hear it.

Frequent contributor Bennett Haselton writes this week with his favorite novelty science gift items for 2012. Levitation engines, puzzles, optical illusions brought to life, and all of the tips and tricks he's found for getting the products to work correctly. Decorative, whimsical, and not too expensive — except for the items that have earned it by being pretty amazing. Read on for the details, and be sure to mention other good possibilities (Just 14 shopping days left until Christmas) in the comments below.

You already know how to find all the latest iPad or iPhone accessories, or how to find all the licensed merchandise if your BFF is a fan of some specific franchise. The items in this list are things that most people wouldn't even think to look for, but that I thought seemed interesting once I found out that they existed.

I'm more of a science geek than a gadget geek, so this list is built around optical illusions, whimsy, conversation pieces that demonstrate some scientific principle, and a reasonable budget. (The "Swinging Sticks Kinetic Energy Sculpture" from ThinkGeek is a work of art, but at $225, the price is apparently set to extract as much as possible from all the people who have to have one after seeing it in Iron Man 2.)

Also, unless otherwise noted, I've actually tried everything listed here and verified that it actually works; there were some items that I really wanted to make work, but couldn't. The Double Sand Sculpture, for example, looks great (especially in colors other than that ugly orange), but in all three models that American Science & Surplus sent me — the original plus the two free replacements — air bubbles formed in the hourglasses after a few days, which blocked the sand grains from flowing through the apertures. I could also never get Educational Innovations' Color Changing Nail Polish to change color, even under a UV light. And I loved the look of the Tornado Fountain from Fascinations.com, but no matter how I calibrated it, the drain at the bottom made a squirting and scraping sound like the last dregs of water draining from a bathtub, which pretty much killed its potential as a "tranquil" conversation piece. (As far as I can tell, any tabletop water fountain that costs less than $100 is either too noisy or doesn't work, but I haven't given up looking.) Of course, if you can get any of those things to work, more power to you.

For most of these items I've included the tips and tricks that I've accumulated for getting the full effect out of the product, tips that in some cases would have saved me a lot of hassle if I'd known them when the product first arrived. So you get the full benefit of my impulsive early-September Christmas shopping.

Neither I nor Slashdot make any profit from these links (except some items are from ThinkGeek, which is a corporate cousin of Slashdot for a few more weeks — but I didn't know that when I was making this list, and besides, it's not like you can put together a geek gift guide without including some stuff from ThinkGeek anyway).

Here are some of the things I've found that look as cool in person as they do in their catalog photos, and actually work:

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Levitron Revolution
Made by Fascinations.com, $100 from Innovatoys.com.

I bought my first "Levitron"-branded product out of a Sky Mall catalog 15 years ago, assuming the picture of the levitating spinning top had to be a doctored photo, and half-set on proving that the product was a sham. I had spent enough time trying to levitate repelling magnets as a kid to conclude that it "couldn't be done," but I held out the faintest glimmer of hope that this might be the holy grail that I'd given up chasing about 10 years earlier. When the box arrived, I spent all evening and a sleepness night trying to get it working (the original product had to be calibrated and balanced very carefully, and you could waste a lot of time trying to make it work if the weights or alignments were slightly off), until just as the sun was coming up, I got the spinning top to levitate above the magnetic base for about four seconds before falling, and felt as if it had all been worth it. And the Levitron product line has come a long way since then, so you probably won't have to journey to the edge of your sanity to get this latest one working.

The Levitron Revolution is a levitation device which uses a base containing four computer-controlled magnets, and a magnetic disc that levitates about 1/2-inch above the base and can support a weight of up to 1 pound placed on top of it while continuing to levitate. It still takes a bit of practice to learn how to position the disc above the base to start the levitation, but the payoff is worth the effort. You can even rotate the base sideways and upside down, and the levitating disc will stay in the same position relative to the base while you turn it.

I used mine to levitate a crystal specimen that I got from a specialty gem store, which set me back about another $30, but I liked the way it glittered in the lights from the magnetic base. The rock was labeled "quartz / pyrite / sphalerite" at the store, and if you're looking for a similar rock to go with the Levitron Revolution, it looks like you can find one on Google Shopping for less than I paid for mine.

You can also use the Levitron Revolution for homemade illusions like levitating a cupcake in mid-air. (A Hostess dessert cup has a circular cavity on top to hold strawberries and whipped cream; turn it upside down and it fits perfectly over the Levitron disc. The book underneath the cupcake in the video was hollowed out to contain the magnetic base.)

Innovatoys sells several other Levitron products made by Fascinations, which all fall into two categories: those based on the classic Levitron design (which include any product showing the yellow-necked Levitron spinning top), and those based on the newer Levitron Revolution technology (everything else). I also have a Levitron CherryWood which is part of the "classic" lineup. The pros and cons of the two series are:

• The classic Levitron levitates the spinning top a full two inches above the base, which is much more visually impressive than the 1/2-inch that the magnetic disc floats above the base of the Levitron Revolution.
• The classic Levitron has to be hand-spun, however, and takes even more practice to operate than the Levitron Revolution.
• The classic Levitron has to be perfectly level for the top to float (the base comes with three adjustable legs to help you level it perfectly); the Levitron Revolution can be tilted and rotated, and the magnetic disc will continue to float in position relative to the base.
• The classic Levitron levitates in a very delicate equilibrium, with just the slightest touch being enough to push the floating top out out of balance and make it fall, so it can't be used to support other objects (and the top is spinning so fast that you wouldn't be able to see anything attached to it anyway). The Levitron Revolution floating disc can be touched and objects can be placed on top of it without pushing it out of equilibrium.
• The classic Levitron requires no power to operate, but because the top has to keep spinning at a high rate for the gyroscopic force to keep it from flipping over, after about two minutes the air friction will slow down the top enough that it falls. The Levitron Revolution will levitate forever as long as the DC power supply is connected.

The Levitron invention itself has something of a contentious history (recounted here and here). Evidently, the physicist Ray Harrigan had patented a similar device a few years earlier and showed it to Bill Hones, who later got his own patent for a similar device and called it the "Levitron," but Hones was advised by his own lawyer that his own invention was sufficiently different from Harrigan's that he could market it without infringing Harrigan's patent or giving him credit or royalties. Apparently Harrigan was so disgusted and distrustful of his own lawyer that he never took the issue to court, so we'll never know what a judge would have thought. (The only issue which was ever litigated in court was over a former re-seller's use of the trademark "Levitron" — but that seems more straightforward, since the company that made up the word and trademarked it, owns it, completely separate from the merits of the invention that bears the name.) Some physicists have mixed feelings about the Levitron because of this, but it was apparently Harrigan's choice not to pursue the issue. (Besides, the new Levitron Revolution design uses nothing of Harrigan's idea, so some might feel that it's less "tainted".)

For cheaper levitation that takes no skill to operate, you can get the Diamagnetic Levitation Kit from Educational Innovations or search for pyrolitic graphite levitation on eBay — much less visually impressive though, with the graphite sheet levitating only 1 millimeter above the magnets.

Or for a more expensive conversation piece, the Levitron Lamp ($450 from InnovaToys or $400 from WorldToHome) levitates an entire lampshade above the base. I haven't tried that one out though.

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Levitating Picture Frames
Heart-shaped frame $25 from ZOpid; rectangular frame $70 from Hammacher Schlemmer.

Computer-controlled levitation operating on a similar principle to the Levitron Revolution products. The $25 ZOpid picture frame is currently hanging out in Amazon limbo with a solitary 1-star review from a customer whose model broke after 4 months. But I think they look fine, and I'm giving two of them as gifts and crossing my fingers that I'm not that unlucky. With both the ZOpid and the Hammacher Schlemmer frames, unfortunately, there's apparently no way to switch off the LED lights (short of turning off the whole model).

Protip: You can prepare these as gifts by using photos downloaded from a friend's Facebook profile, but Facebook reduces the quality of uploaded photos, so that if you print them out, the pixellation will be noticeable up close. If you want the photos to look the best, you need to print them from high-res originals.

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Hanayama Japanese Pocket Puzzles
$13 from ThinkGeek and other vendors; some puzzles available for slightly less on eBay.

Some disassembly puzzles are complete fails, either because there are so many separately moving pieces that you can't manipulate the puzzles in your hands at all (e.g. Yin and Yang"), or the moving parts are hidden from view so you can only "solve" them by pure guesswork (e.g. the "Bolted Closed" puzzle). The Hanayama pocket puzzles actually get it right — you can see all the pieces and move them comfortably in your hands, so solving them is just a matter of figuring out the right sequence of moves.

These are basically grown-up versions of the twisted nail puzzles you might have grown up with (and which you could also get, of course, as much cheaper stocking stuffers). But the Hanayama ones look good as shelf knick-knacks as well.

Hanayama pocket puzzles come with no solution included, but you can download a solution by going to this page and submitting your email address to request a download link.

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LED Jellyfish Mood Lamp
$35 from ThinkGeek and other vendors; no cheaper alternatives on eBay

Works more or less as shown in the video, with one caveat: In both the first model that I tried, and the free replacement ThinkGeek sent me when I reported the problem, the transitions between the different colors were much more abrupt and jarring than the smooth "color fade" shown in the video. (For some reason, some color LEDs would switch from completely on to completely off at the same time that other LEDs would switch on.) Unfortunately this small problem completely breaks the "reverie" effect of staring at the jellyfish floating around in the water, so I just set mine to a single color without using the transition effect.

Protip: You have to use real distilled water like the instructions tell you. I tried to make it work with regular tap water, and bubbles kept forming around the jellyfish and causing them to float to the surface. Fill it with distilled water and the jellyfish should sink beneath the surface without too much trouble.

Note, Fascinations has come out with a similar product, again sold on Innovatoys.com; I haven't tried that one, so it might be better (might actually get the color transition right), or it might not. Discovery Kids also makes a similar product which I haven't seen and which has been pulling pretty bad reviews on Amazon.

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Vino Vault and Cryptex Puzzle Pod
$30 and $22 from 4Thought Products LLC

The Puzzle Pod is a gift container that can only be opened by arranging the 5 rings to spell out a 5-letter password. It arrives pre-configured with the keyword "GRAPE"; once opened, you can re-configure the Pod with a new 5-letter secret word, seal a gift inside, and gift it to a recipient who has to find the secret word to open the puzzle and retrieve the gift. (It's re-usable, and you can set a different 5-letter "password" every time.) The Vino Vault is a larger version of the Puzzle Pod that can hold a bottle of wine.

I've only sampled the Puzzle Pod, so I can just vouch for the fact that it works exactly as described and doesn't get stuck or break easily. When you line up the letters of the secret word correctly, it actually slides smoothly open like it's supposed to.

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Ambiguous Vase
$33 from Grand Illusions Ltd (ships from the UK)

This is a real-life version of the Rubin vase optical illusion. For years, Grand Illusions sold only a ceramic version for about $400 (plus another $200 to ship to the U.S.), but in November 2012 they released the $33 plastic version. It can also be used as a real vase (as long as you don't mind the barrier running down the center that divides the two halves).

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Steam Powered Top
$14 from Grand Illusions (ships from the UK)

The world's simplest steam engine, made from a tube of copper pushed through a piece of cork, as shown in the demo video. Wikipedia explains the principle here — when the water in the copper tube is heated by the candle flame and boils, it expands and pushes out the ends of the tubes (driving the spinning motion). When the water contracts again, in sucks in water through the ends of the tubes — but the sucking motion pulls in water from all directions (while the expulsion of water pushes in only one direction), so the suction doesn't counteract the propulsion, and the top continues spinning.

Now, the original version is from Germany (and comes with detailed German instructions); the version that I got came with a sheet of English instructions that weren't as detailed. The instructions say to push the copper tube through the cork platform and "bend the tube at a 90-degree angle"; however if you just try bending the tube, it will probably crimp and create a hole, making it useless. To bend the tube so that it curves gradually, place your thumb on the cork next to where the tube protrudes, and use the fingers of your other hand to gently push the tube so that curves around your thumb. (This is spelled out in the original German instructions.)

Also, the instructions say to fill the copper tube by holding it under running tap water. This didn't work at all for me, since the tube is only about 2mm wide and the surface tension of water makes it hard to "push" it into a tube that small. Fortunately, a straw from a grocery-store juicebox fits perfectly over the other end of the copper tube, so if you submerge the other end in water, you can suck on the straw to fill the tube that way. (It's just copper after all, not lead.)

Finally, if you leave the cork floating in water too long, it eventually gets waterlogged and sinks, and as far as I can tell it's very hard to dry it out and bring it back to its original buoyancy. The workarounds for this are: (1) to increase the buoyancy, first put another tea light directly into your bowl of water so that it floats, and then lower the top into the water on top of that tea light, which will then help keep the top afloat; and (2) don't leave the top floating in water when not in use.

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"Flying F*CK" Remote-Control Helicopter
$20 from ThinkGeek

Again with the ThinkGeek swag; I swear I didn't know.

This is pretty self-explanatory, except I've tried two of them and the product doesn't seem to work too well as an actual remote-control helicopter; one of them couldn't hover in place (its two modes were "shooting up at the ceiling" or "falling"), and with the other, the R/C didn't seem to work through furniture. But that's probably OK since the whole point of this gift is in the giving and not the having.

In my case, I hid it behind a friend's chair at his birthday party, then at the appropriate time gave a speech ending with, "And so I thought, what do I give my friend to mark this occasion? What do I give? After much thought, I decided, this is what I give:..." There followed a dramatic pause where I pressed the "up" control on the remote, and nothing happened, whereupon I muttered, appropriately enough, "Fuck", then wandered over behind my friend's chair, repeated the setup line, pressed the remote button, at which point the copter shot up, banged into a chair and fell to the ground, whereupon for my third attempt I just picked it up and held it on the palm of my hand, pressed the remote, and the copter took flight and finally delivered the punch line, and all was good. If I'm there when he re-gifts it (since we both agreed that was the point of a gift like this), I hope it works better for him.

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Falling Sand Sculptures
$13 for the smaller 'Sandscape'; $80 for the larger 'Deep Sea Round'; both available from Educational Innovations

These both make good decorations and shelf widgets. The sand in the Sandscape always falls in more or less the same pattern, since it's pre-determined by the gaps in the shelves holding the sand; the Deep Sea Round is more interesting since the pattern is determined by the placement of air bubbles and varies every time.

Pro tip: water evaporates from both of these, so eventually the water level will drop and the volume of air will increase, getting in the way of the sand flow. The 'Deep Sea Round' comes with a syringe that you can use to draw out air and inject more water into the aperture on the side. The cheaper 'Sandscape' doesn't come with a syringe, but it has a hole in the side where you can use a syringe to inject more water, if you buy the syringe separately.

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Galileo Thermometer
$17 for a wood-mounted model from Office Playground; cheaper ones available without wood mounting

Just your basic elegant conversation piece demonstrating the principle that the density of a liquid changes with temperature. Pro tip: If you get the wood mounted one, before emailing the seller to complain that it's not working because all the spheres are bunched together at the wrong end, make sure it's not upside-down. (I realized, before I hit Send, that the felt-covered end goes on the bottom.)

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All of the remaining items on this list do exactly what they say they do, with no need for any special instructions not included by the manufacturer, so I'm just going to list them:

Glass Water Faucet — $50 from Uncommon Goods — a nice double optical illusion (faucet suspended in space, and glass-as-water).

Slicked Grandfather Clock — $30-$60 depending on who's selling it.

Tin Can Robot Kit — about $15 from various vendors — my stepdad and I assembled one using one of his beloved Hansen's soda cans.

Mini metal DIY sculptures — the Metal Works sculptures from Innovatoys ($7-$12) take some time to assemble but they come out looking pretty much like the pictures and make good shelf decorations. These Mikro sculptures ($10 and up, also available from Grand Illusions if you're filling your shopping cart there) are a bit easier to assemble since you just have to bend some shapes out from the metal sheet that they're carved from.

Ulexite "Television Stones" — $10 from Educational Innovations — a naturally occuring rock containing thousands of parallel fiber optic strands. Give it as a gift together with a square of patterned fabric so you can see the eerie effect when you place the rock against the fabric and the pattern "magically" appears on the opposite side of the rock.

And finally, if you need a last-minute gag gift for someone, browse through the gum and hand sanitizers from BlueQ.com — they're not geek-themed, but at $5.49 for the hand sanitizers and $1.39 for the gum, you can afford to stock up so you'll have a reserve of gag gifts suited for a variety of different people's tastes (except, of course, good taste).

And those are my favorites for gift-giving season 2012. You can send me suggestions for any items in this category that I've missed; I'll be back for Valentine's Day.

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Remember, if you have a feature idea, we'd love to hear it.

Frequent contributor Bennett Haselton writes this week with his favorite novelty science gift items for 2012. Levitation engines, puzzles, optical illusions brought to life, and all of the tips and tricks he's found for getting the products to work correctly. Decorative, whimsical, and not too expensive — except for the items that have earned it by being pretty amazing. Read on for the details, and be sure to mention other good possibilities (Just 14 shopping days left until Christmas) in the comments below.

You already know how to find all the latest iPad or iPhone accessories, or how to find all the licensed merchandise if your BFF is a fan of some specific franchise. The items in this list are things that most people wouldn't even think to look for, but that I thought seemed interesting once I found out that they existed.

I'm more of a science geek than a gadget geek, so this list is built around optical illusions, whimsy, conversation pieces that demonstrate some scientific principle, and a reasonable budget. (The "Swinging Sticks Kinetic Energy Sculpture" from ThinkGeek is a work of art, but at $225, the price is apparently set to extract as much as possible from all the people who have to have one after seeing it in Iron Man 2.)

Also, unless otherwise noted, I've actually tried everything listed here and verified that it actually works; there were some items that I really wanted to make work, but couldn't. The Double Sand Sculpture, for example, looks great (especially in colors other than that ugly orange), but in all three models that American Science & Surplus sent me — the original plus the two free replacements — air bubbles formed in the hourglasses after a few days, which blocked the sand grains from flowing through the apertures. I could also never get Educational Innovations' Color Changing Nail Polish to change color, even under a UV light. And I loved the look of the Tornado Fountain from Fascinations.com, but no matter how I calibrated it, the drain at the bottom made a squirting and scraping sound like the last dregs of water draining from a bathtub, which pretty much killed its potential as a "tranquil" conversation piece. (As far as I can tell, any tabletop water fountain that costs less than $100 is either too noisy or doesn't work, but I haven't given up looking.) Of course, if you can get any of those things to work, more power to you.

For most of these items I've included the tips and tricks that I've accumulated for getting the full effect out of the product, tips that in some cases would have saved me a lot of hassle if I'd known them when the product first arrived. So you get the full benefit of my impulsive early-September Christmas shopping.

Neither I nor Slashdot make any profit from these links (except some items are from ThinkGeek, which is a corporate cousin of Slashdot for a few more weeks — but I didn't know that when I was making this list, and besides, it's not like you can put together a geek gift guide without including some stuff from ThinkGeek anyway).

Here are some of the things I've found that look as cool in person as they do in their catalog photos, and actually work:

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Levitron Revolution
Made by Fascinations.com, $100 from Innovatoys.com.

I bought my first "Levitron"-branded product out of a Sky Mall catalog 15 years ago, assuming the picture of the levitating spinning top had to be a doctored photo, and half-set on proving that the product was a sham. I had spent enough time trying to levitate repelling magnets as a kid to conclude that it "couldn't be done," but I held out the faintest glimmer of hope that this might be the holy grail that I'd given up chasing about 10 years earlier. When the box arrived, I spent all evening and a sleepness night trying to get it working (the original product had to be calibrated and balanced very carefully, and you could waste a lot of time trying to make it work if the weights or alignments were slightly off), until just as the sun was coming up, I got the spinning top to levitate above the magnetic base for about four seconds before falling, and felt as if it had all been worth it. And the Levitron product line has come a long way since then, so you probably won't have to journey to the edge of your sanity to get this latest one working.

The Levitron Revolution is a levitation device which uses a base containing four computer-controlled magnets, and a magnetic disc that levitates about 1/2-inch above the base and can support a weight of up to 1 pound placed on top of it while continuing to levitate. It still takes a bit of practice to learn how to position the disc above the base to start the levitation, but the payoff is worth the effort. You can even rotate the base sideways and upside down, and the levitating disc will stay in the same position relative to the base while you turn it.

I used mine to levitate a crystal specimen that I got from a specialty gem store, which set me back about another $30, but I liked the way it glittered in the lights from the magnetic base. The rock was labeled "quartz / pyrite / sphalerite" at the store, and if you're looking for a similar rock to go with the Levitron Revolution, it looks like you can find one on Google Shopping for less than I paid for mine.

You can also use the Levitron Revolution for homemade illusions like levitating a cupcake in mid-air. (A Hostess dessert cup has a circular cavity on top to hold strawberries and whipped cream; turn it upside down and it fits perfectly over the Levitron disc. The book underneath the cupcake in the video was hollowed out to contain the magnetic base.)

Innovatoys sells several other Levitron products made by Fascinations, which all fall into two categories: those based on the classic Levitron design (which include any product showing the yellow-necked Levitron spinning top), and those based on the newer Levitron Revolution technology (everything else). I also have a Levitron CherryWood which is part of the "classic" lineup. The pros and cons of the two series are:

• The classic Levitron levitates the spinning top a full two inches above the base, which is much more visually impressive than the 1/2-inch that the magnetic disc floats above the base of the Levitron Revolution.
• The classic Levitron has to be hand-spun, however, and takes even more practice to operate than the Levitron Revolution.
• The classic Levitron has to be perfectly level for the top to float (the base comes with three adjustable legs to help you level it perfectly); the Levitron Revolution can be tilted and rotated, and the magnetic disc will continue to float in position relative to the base.
• The classic Levitron levitates in a very delicate equilibrium, with just the slightest touch being enough to push the floating top out out of balance and make it fall, so it can't be used to support other objects (and the top is spinning so fast that you wouldn't be able to see anything attached to it anyway). The Levitron Revolution floating disc can be touched and objects can be placed on top of it without pushing it out of equilibrium.
• The classic Levitron requires no power to operate, but because the top has to keep spinning at a high rate for the gyroscopic force to keep it from flipping over, after about two minutes the air friction will slow down the top enough that it falls. The Levitron Revolution will levitate forever as long as the DC power supply is connected.

The Levitron invention itself has something of a contentious history (recounted here and here). Evidently, the physicist Ray Harrigan had patented a similar device a few years earlier and showed it to Bill Hones, who later got his own patent for a similar device and called it the "Levitron," but Hones was advised by his own lawyer that his own invention was sufficiently different from Harrigan's that he could market it without infringing Harrigan's patent or giving him credit or royalties. Apparently Harrigan was so disgusted and distrustful of his own lawyer that he never took the issue to court, so we'll never know what a judge would have thought. (The only issue which was ever litigated in court was over a former re-seller's use of the trademark "Levitron" — but that seems more straightforward, since the company that made up the word and trademarked it, owns it, completely separate from the merits of the invention that bears the name.) Some physicists have mixed feelings about the Levitron because of this, but it was apparently Harrigan's choice not to pursue the issue. (Besides, the new Levitron Revolution design uses nothing of Harrigan's idea, so some might feel that it's less "tainted".)

For cheaper levitation that takes no skill to operate, you can get the Diamagnetic Levitation Kit from Educational Innovations or search for pyrolitic graphite levitation on eBay — much less visually impressive though, with the graphite sheet levitating only 1 millimeter above the magnets.

Or for a more expensive conversation piece, the Levitron Lamp ($450 from InnovaToys or $400 from WorldToHome) levitates an entire lampshade above the base. I haven't tried that one out though.

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Levitating Picture Frames
Heart-shaped frame $25 from ZOpid; rectangular frame $70 from Hammacher Schlemmer.

Computer-controlled levitation operating on a similar principle to the Levitron Revolution products. The $25 ZOpid picture frame is currently hanging out in Amazon limbo with a solitary 1-star review from a customer whose model broke after 4 months. But I think they look fine, and I'm giving two of them as gifts and crossing my fingers that I'm not that unlucky. With both the ZOpid and the Hammacher Schlemmer frames, unfortunately, there's apparently no way to switch off the LED lights (short of turning off the whole model).

Protip: You can prepare these as gifts by using photos downloaded from a friend's Facebook profile, but Facebook reduces the quality of uploaded photos, so that if you print them out, the pixellation will be noticeable up close. If you want the photos to look the best, you need to print them from high-res originals.

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Hanayama Japanese Pocket Puzzles
$13 from ThinkGeek and other vendors; some puzzles available for slightly less on eBay.

Some disassembly puzzles are complete fails, either because there are so many separately moving pieces that you can't manipulate the puzzles in your hands at all (e.g. Yin and Yang"), or the moving parts are hidden from view so you can only "solve" them by pure guesswork (e.g. the "Bolted Closed" puzzle). The Hanayama pocket puzzles actually get it right — you can see all the pieces and move them comfortably in your hands, so solving them is just a matter of figuring out the right sequence of moves.

These are basically grown-up versions of the twisted nail puzzles you might have grown up with (and which you could also get, of course, as much cheaper stocking stuffers). But the Hanayama ones look good as shelf knick-knacks as well.

Hanayama pocket puzzles come with no solution included, but you can download a solution by going to this page and submitting your email address to request a download link.

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LED Jellyfish Mood Lamp
$35 from ThinkGeek and other vendors; no cheaper alternatives on eBay

Works more or less as shown in the video, with one caveat: In both the first model that I tried, and the free replacement ThinkGeek sent me when I reported the problem, the transitions between the different colors were much more abrupt and jarring than the smooth "color fade" shown in the video. (For some reason, some color LEDs would switch from completely on to completely off at the same time that other LEDs would switch on.) Unfortunately this small problem completely breaks the "reverie" effect of staring at the jellyfish floating around in the water, so I just set mine to a single color without using the transition effect.

Protip: You have to use real distilled water like the instructions tell you. I tried to make it work with regular tap water, and bubbles kept forming around the jellyfish and causing them to float to the surface. Fill it with distilled water and the jellyfish should sink beneath the surface without too much trouble.

Note, Fascinations has come out with a similar product, again sold on Innovatoys.com; I haven't tried that one, so it might be better (might actually get the color transition right), or it might not. Discovery Kids also makes a similar product which I haven't seen and which has been pulling pretty bad reviews on Amazon.

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Vino Vault and Cryptex Puzzle Pod
$30 and $22 from 4Thought Products LLC

The Puzzle Pod is a gift container that can only be opened by arranging the 5 rings to spell out a 5-letter password. It arrives pre-configured with the keyword "GRAPE"; once opened, you can re-configure the Pod with a new 5-letter secret word, seal a gift inside, and gift it to a recipient who has to find the secret word to open the puzzle and retrieve the gift. (It's re-usable, and you can set a different 5-letter "password" every time.) The Vino Vault is a larger version of the Puzzle Pod that can hold a bottle of wine.

I've only sampled the Puzzle Pod, so I can just vouch for the fact that it works exactly as described and doesn't get stuck or break easily. When you line up the letters of the secret word correctly, it actually slides smoothly open like it's supposed to.

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Ambiguous Vase
$33 from Grand Illusions Ltd (ships from the UK)

This is a real-life version of the Rubin vase optical illusion. For years, Grand Illusions sold only a ceramic version for about $400 (plus another $200 to ship to the U.S.), but in November 2012 they released the $33 plastic version. It can also be used as a real vase (as long as you don't mind the barrier running down the center that divides the two halves).

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Steam Powered Top
$14 from Grand Illusions (ships from the UK)

The world's simplest steam engine, made from a tube of copper pushed through a piece of cork, as shown in the demo video. Wikipedia explains the principle here — when the water in the copper tube is heated by the candle flame and boils, it expands and pushes out the ends of the tubes (driving the spinning motion). When the water contracts again, in sucks in water through the ends of the tubes — but the sucking motion pulls in water from all directions (while the expulsion of water pushes in only one direction), so the suction doesn't counteract the propulsion, and the top continues spinning.

Now, the original version is from Germany (and comes with detailed German instructions); the version that I got came with a sheet of English instructions that weren't as detailed. The instructions say to push the copper tube through the cork platform and "bend the tube at a 90-degree angle"; however if you just try bending the tube, it will probably crimp and create a hole, making it useless. To bend the tube so that it curves gradually, place your thumb on the cork next to where the tube protrudes, and use the fingers of your other hand to gently push the tube so that curves around your thumb. (This is spelled out in the original German instructions.)

Also, the instructions say to fill the copper tube by holding it under running tap water. This didn't work at all for me, since the tube is only about 2mm wide and the surface tension of water makes it hard to "push" it into a tube that small. Fortunately, a straw from a grocery-store juicebox fits perfectly over the other end of the copper tube, so if you submerge the other end in water, you can suck on the straw to fill the tube that way. (It's just copper after all, not lead.)

Finally, if you leave the cork floating in water too long, it eventually gets waterlogged and sinks, and as far as I can tell it's very hard to dry it out and bring it back to its original buoyancy. The workarounds for this are: (1) to increase the buoyancy, first put another tea light directly into your bowl of water so that it floats, and then lower the top into the water on top of that tea light, which will then help keep the top afloat; and (2) don't leave the top floating in water when not in use.

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"Flying F*CK" Remote-Control Helicopter
$20 from ThinkGeek

Again with the ThinkGeek swag; I swear I didn't know.

This is pretty self-explanatory, except I've tried two of them and the product doesn't seem to work too well as an actual remote-control helicopter; one of them couldn't hover in place (its two modes were "shooting up at the ceiling" or "falling"), and with the other, the R/C didn't seem to work through furniture. But that's probably OK since the whole point of this gift is in the giving and not the having.

In my case, I hid it behind a friend's chair at his birthday party, then at the appropriate time gave a speech ending with, "And so I thought, what do I give my friend to mark this occasion? What do I give? After much thought, I decided, this is what I give:..." There followed a dramatic pause where I pressed the "up" control on the remote, and nothing happened, whereupon I muttered, appropriately enough, "Fuck", then wandered over behind my friend's chair, repeated the setup line, pressed the remote button, at which point the copter shot up, banged into a chair and fell to the ground, whereupon for my third attempt I just picked it up and held it on the palm of my hand, pressed the remote, and the copter took flight and finally delivered the punch line, and all was good. If I'm there when he re-gifts it (since we both agreed that was the point of a gift like this), I hope it works better for him.

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Falling Sand Sculptures
$13 for the smaller 'Sandscape'; $80 for the larger 'Deep Sea Round'; both available from Educational Innovations

These both make good decorations and shelf widgets. The sand in the Sandscape always falls in more or less the same pattern, since it's pre-determined by the gaps in the shelves holding the sand; the Deep Sea Round is more interesting since the pattern is determined by the placement of air bubbles and varies every time.

Pro tip: water evaporates from both of these, so eventually the water level will drop and the volume of air will increase, getting in the way of the sand flow. The 'Deep Sea Round' comes with a syringe that you can use to draw out air and inject more water into the aperture on the side. The cheaper 'Sandscape' doesn't come with a syringe, but it has a hole in the side where you can use a syringe to inject more water, if you buy the syringe separately.

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Galileo Thermometer
$17 for a wood-mounted model from Office Playground; cheaper ones available without wood mounting

Just your basic elegant conversation piece demonstrating the principle that the density of a liquid changes with temperature. Pro tip: If you get the wood mounted one, before emailing the seller to complain that it's not working because all the spheres are bunched together at the wrong end, make sure it's not upside-down. (I realized, before I hit Send, that the felt-covered end goes on the bottom.)

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All of the remaining items on this list do exactly what they say they do, with no need for any special instructions not included by the manufacturer, so I'm just going to list them:

Glass Water Faucet — $50 from Uncommon Goods — a nice double optical illusion (faucet suspended in space, and glass-as-water).

Slicked Grandfather Clock — $30-$60 depending on who's selling it.

Tin Can Robot Kit — about $15 from various vendors — my stepdad and I assembled one using one of his beloved Hansen's soda cans.

Mini metal DIY sculptures — the Metal Works sculptures from Innovatoys ($7-$12) take some time to assemble but they come out looking pretty much like the pictures and make good shelf decorations. These Mikro sculptures ($10 and up, also available from Grand Illusions if you're filling your shopping cart there) are a bit easier to assemble since you just have to bend some shapes out from the metal sheet that they're carved from.

Ulexite "Television Stones" — $10 from Educational Innovations — a naturally occuring rock containing thousands of parallel fiber optic strands. Give it as a gift together with a square of patterned fabric so you can see the eerie effect when you place the rock against the fabric and the pattern "magically" appears on the opposite side of the rock.

And finally, if you need a last-minute gag gift for someone, browse through the gum and hand sanitizers from BlueQ.com — they're not geek-themed, but at $5.49 for the hand sanitizers and $1.39 for the gum, you can afford to stock up so you'll have a reserve of gag gifts suited for a variety of different people's tastes (except, of course, good taste).

And those are my favorites for gift-giving season 2012. You can send me suggestions for any items in this category that I've missed; I'll be back for Valentine's Day.

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Remember, if you have a feature idea, we'd love to hear it.

Frequent contributor Bennett Haselton writes this week with his favorite novelty science gift items for 2012. Levitation engines, puzzles, optical illusions brought to life, and all of the tips and tricks he's found for getting the products to work correctly. Decorative, whimsical, and not too expensive — except for the items that have earned it by being pretty amazing. Read on for the details, and be sure to mention other good possibilities (Just 14 shopping days left until Christmas) in the comments below.

You already know how to find all the latest iPad or iPhone accessories, or how to find all the licensed merchandise if your BFF is a fan of some specific franchise. The items in this list are things that most people wouldn't even think to look for, but that I thought seemed interesting once I found out that they existed.

I'm more of a science geek than a gadget geek, so this list is built around optical illusions, whimsy, conversation pieces that demonstrate some scientific principle, and a reasonable budget. (The "Swinging Sticks Kinetic Energy Sculpture" from ThinkGeek is a work of art, but at $225, the price is apparently set to extract as much as possible from all the people who have to have one after seeing it in Iron Man 2.)

Also, unless otherwise noted, I've actually tried everything listed here and verified that it actually works; there were some items that I really wanted to make work, but couldn't. The Double Sand Sculpture, for example, looks great (especially in colors other than that ugly orange), but in all three models that American Science & Surplus sent me — the original plus the two free replacements — air bubbles formed in the hourglasses after a few days, which blocked the sand grains from flowing through the apertures. I could also never get Educational Innovations' Color Changing Nail Polish to change color, even under a UV light. And I loved the look of the Tornado Fountain from Fascinations.com, but no matter how I calibrated it, the drain at the bottom made a squirting and scraping sound like the last dregs of water draining from a bathtub, which pretty much killed its potential as a "tranquil" conversation piece. (As far as I can tell, any tabletop water fountain that costs less than $100 is either too noisy or doesn't work, but I haven't given up looking.) Of course, if you can get any of those things to work, more power to you.

For most of these items I've included the tips and tricks that I've accumulated for getting the full effect out of the product, tips that in some cases would have saved me a lot of hassle if I'd known them when the product first arrived. So you get the full benefit of my impulsive early-September Christmas shopping.

Neither I nor Slashdot make any profit from these links (except some items are from ThinkGeek, which is a corporate cousin of Slashdot for a few more weeks — but I didn't know that when I was making this list, and besides, it's not like you can put together a geek gift guide without including some stuff from ThinkGeek anyway).

Here are some of the things I've found that look as cool in person as they do in their catalog photos, and actually work:

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Levitron Revolution
Made by Fascinations.com, $100 from Innovatoys.com.

I bought my first "Levitron"-branded product out of a Sky Mall catalog 15 years ago, assuming the picture of the levitating spinning top had to be a doctored photo, and half-set on proving that the product was a sham. I had spent enough time trying to levitate repelling magnets as a kid to conclude that it "couldn't be done," but I held out the faintest glimmer of hope that this might be the holy grail that I'd given up chasing about 10 years earlier. When the box arrived, I spent all evening and a sleepness night trying to get it working (the original product had to be calibrated and balanced very carefully, and you could waste a lot of time trying to make it work if the weights or alignments were slightly off), until just as the sun was coming up, I got the spinning top to levitate above the magnetic base for about four seconds before falling, and felt as if it had all been worth it. And the Levitron product line has come a long way since then, so you probably won't have to journey to the edge of your sanity to get this latest one working.

The Levitron Revolution is a levitation device which uses a base containing four computer-controlled magnets, and a magnetic disc that levitates about 1/2-inch above the base and can support a weight of up to 1 pound placed on top of it while continuing to levitate. It still takes a bit of practice to learn how to position the disc above the base to start the levitation, but the payoff is worth the effort. You can even rotate the base sideways and upside down, and the levitating disc will stay in the same position relative to the base while you turn it.

I used mine to levitate a crystal specimen that I got from a specialty gem store, which set me back about another $30, but I liked the way it glittered in the lights from the magnetic base. The rock was labeled "quartz / pyrite / sphalerite" at the store, and if you're looking for a similar rock to go with the Levitron Revolution, it looks like you can find one on Google Shopping for less than I paid for mine.

You can also use the Levitron Revolution for homemade illusions like levitating a cupcake in mid-air. (A Hostess dessert cup has a circular cavity on top to hold strawberries and whipped cream; turn it upside down and it fits perfectly over the Levitron disc. The book underneath the cupcake in the video was hollowed out to contain the magnetic base.)

Innovatoys sells several other Levitron products made by Fascinations, which all fall into two categories: those based on the classic Levitron design (which include any product showing the yellow-necked Levitron spinning top), and those based on the newer Levitron Revolution technology (everything else). I also have a Levitron CherryWood which is part of the "classic" lineup. The pros and cons of the two series are:

• The classic Levitron levitates the spinning top a full two inches above the base, which is much more visually impressive than the 1/2-inch that the magnetic disc floats above the base of the Levitron Revolution.
• The classic Levitron has to be hand-spun, however, and takes even more practice to operate than the Levitron Revolution.
• The classic Levitron has to be perfectly level for the top to float (the base comes with three adjustable legs to help you level it perfectly); the Levitron Revolution can be tilted and rotated, and the magnetic disc will continue to float in position relative to the base.
• The classic Levitron levitates in a very delicate equilibrium, with just the slightest touch being enough to push the floating top out out of balance and make it fall, so it can't be used to support other objects (and the top is spinning so fast that you wouldn't be able to see anything attached to it anyway). The Levitron Revolution floating disc can be touched and objects can be placed on top of it without pushing it out of equilibrium.
• The classic Levitron requires no power to operate, but because the top has to keep spinning at a high rate for the gyroscopic force to keep it from flipping over, after about two minutes the air friction will slow down the top enough that it falls. The Levitron Revolution will levitate forever as long as the DC power supply is connected.

The Levitron invention itself has something of a contentious history (recounted here and here). Evidently, the physicist Ray Harrigan had patented a similar device a few years earlier and showed it to Bill Hones, who later got his own patent for a similar device and called it the "Levitron," but Hones was advised by his own lawyer that his own invention was sufficiently different from Harrigan's that he could market it without infringing Harrigan's patent or giving him credit or royalties. Apparently Harrigan was so disgusted and distrustful of his own lawyer that he never took the issue to court, so we'll never know what a judge would have thought. (The only issue which was ever litigated in court was over a former re-seller's use of the trademark "Levitron" — but that seems more straightforward, since the company that made up the word and trademarked it, owns it, completely separate from the merits of the invention that bears the name.) Some physicists have mixed feelings about the Levitron because of this, but it was apparently Harrigan's choice not to pursue the issue. (Besides, the new Levitron Revolution design uses nothing of Harrigan's idea, so some might feel that it's less "tainted".)

For cheaper levitation that takes no skill to operate, you can get the Diamagnetic Levitation Kit from Educational Innovations or search for pyrolitic graphite levitation on eBay — much less visually impressive though, with the graphite sheet levitating only 1 millimeter above the magnets.

Or for a more expensive conversation piece, the Levitron Lamp ($450 from InnovaToys or $400 from WorldToHome) levitates an entire lampshade above the base. I haven't tried that one out though.

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Levitating Picture Frames
Heart-shaped frame $25 from ZOpid; rectangular frame $70 from Hammacher Schlemmer.

Computer-controlled levitation operating on a similar principle to the Levitron Revolution products. The $25 ZOpid picture frame is currently hanging out in Amazon limbo with a solitary 1-star review from a customer whose model broke after 4 months. But I think they look fine, and I'm giving two of them as gifts and crossing my fingers that I'm not that unlucky. With both the ZOpid and the Hammacher Schlemmer frames, unfortunately, there's apparently no way to switch off the LED lights (short of turning off the whole model).

Protip: You can prepare these as gifts by using photos downloaded from a friend's Facebook profile, but Facebook reduces the quality of uploaded photos, so that if you print them out, the pixellation will be noticeable up close. If you want the photos to look the best, you need to print them from high-res originals.

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Hanayama Japanese Pocket Puzzles
$13 from ThinkGeek and other vendors; some puzzles available for slightly less on eBay.

Some disassembly puzzles are complete fails, either because there are so many separately moving pieces that you can't manipulate the puzzles in your hands at all (e.g. Yin and Yang"), or the moving parts are hidden from view so you can only "solve" them by pure guesswork (e.g. the "Bolted Closed" puzzle). The Hanayama pocket puzzles actually get it right — you can see all the pieces and move them comfortably in your hands, so solving them is just a matter of figuring out the right sequence of moves.

These are basically grown-up versions of the twisted nail puzzles you might have grown up with (and which you could also get, of course, as much cheaper stocking stuffers). But the Hanayama ones look good as shelf knick-knacks as well.

Hanayama pocket puzzles come with no solution included, but you can download a solution by going to this page and submitting your email address to request a download link.

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LED Jellyfish Mood Lamp
$35 from ThinkGeek and other vendors; no cheaper alternatives on eBay

Works more or less as shown in the video, with one caveat: In both the first model that I tried, and the free replacement ThinkGeek sent me when I reported the problem, the transitions between the different colors were much more abrupt and jarring than the smooth "color fade" shown in the video. (For some reason, some color LEDs would switch from completely on to completely off at the same time that other LEDs would switch on.) Unfortunately this small problem completely breaks the "reverie" effect of staring at the jellyfish floating around in the water, so I just set mine to a single color without using the transition effect.

Protip: You have to use real distilled water like the instructions tell you. I tried to make it work with regular tap water, and bubbles kept forming around the jellyfish and causing them to float to the surface. Fill it with distilled water and the jellyfish should sink beneath the surface without too much trouble.

Note, Fascinations has come out with a similar product, again sold on Innovatoys.com; I haven't tried that one, so it might be better (might actually get the color transition right), or it might not. Discovery Kids also makes a similar product which I haven't seen and which has been pulling pretty bad reviews on Amazon.

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Vino Vault and Cryptex Puzzle Pod
$30 and $22 from 4Thought Products LLC

The Puzzle Pod is a gift container that can only be opened by arranging the 5 rings to spell out a 5-letter password. It arrives pre-configured with the keyword "GRAPE"; once opened, you can re-configure the Pod with a new 5-letter secret word, seal a gift inside, and gift it to a recipient who has to find the secret word to open the puzzle and retrieve the gift. (It's re-usable, and you can set a different 5-letter "password" every time.) The Vino Vault is a larger version of the Puzzle Pod that can hold a bottle of wine.

I've only sampled the Puzzle Pod, so I can just vouch for the fact that it works exactly as described and doesn't get stuck or break easily. When you line up the letters of the secret word correctly, it actually slides smoothly open like it's supposed to.

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Ambiguous Vase
$33 from Grand Illusions Ltd (ships from the UK)

This is a real-life version of the Rubin vase optical illusion. For years, Grand Illusions sold only a ceramic version for about $400 (plus another $200 to ship to the U.S.), but in November 2012 they released the $33 plastic version. It can also be used as a real vase (as long as you don't mind the barrier running down the center that divides the two halves).

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Steam Powered Top
$14 from Grand Illusions (ships from the UK)

The world's simplest steam engine, made from a tube of copper pushed through a piece of cork, as shown in the demo video. Wikipedia explains the principle here — when the water in the copper tube is heated by the candle flame and boils, it expands and pushes out the ends of the tubes (driving the spinning motion). When the water contracts again, in sucks in water through the ends of the tubes — but the sucking motion pulls in water from all directions (while the expulsion of water pushes in only one direction), so the suction doesn't counteract the propulsion, and the top continues spinning.

Now, the original version is from Germany (and comes with detailed German instructions); the version that I got came with a sheet of English instructions that weren't as detailed. The instructions say to push the copper tube through the cork platform and "bend the tube at a 90-degree angle"; however if you just try bending the tube, it will probably crimp and create a hole, making it useless. To bend the tube so that it curves gradually, place your thumb on the cork next to where the tube protrudes, and use the fingers of your other hand to gently push the tube so that curves around your thumb. (This is spelled out in the original German instructions.)

Also, the instructions say to fill the copper tube by holding it under running tap water. This didn't work at all for me, since the tube is only about 2mm wide and the surface tension of water makes it hard to "push" it into a tube that small. Fortunately, a straw from a grocery-store juicebox fits perfectly over the other end of the copper tube, so if you submerge the other end in water, you can suck on the straw to fill the tube that way. (It's just copper after all, not lead.)

Finally, if you leave the cork floating in water too long, it eventually gets waterlogged and sinks, and as far as I can tell it's very hard to dry it out and bring it back to its original buoyancy. The workarounds for this are: (1) to increase the buoyancy, first put another tea light directly into your bowl of water so that it floats, and then lower the top into the water on top of that tea light, which will then help keep the top afloat; and (2) don't leave the top floating in water when not in use.

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"Flying F*CK" Remote-Control Helicopter
$20 from ThinkGeek

Again with the ThinkGeek swag; I swear I didn't know.

This is pretty self-explanatory, except I've tried two of them and the product doesn't seem to work too well as an actual remote-control helicopter; one of them couldn't hover in place (its two modes were "shooting up at the ceiling" or "falling"), and with the other, the R/C didn't seem to work through furniture. But that's probably OK since the whole point of this gift is in the giving and not the having.

In my case, I hid it behind a friend's chair at his birthday party, then at the appropriate time gave a speech ending with, "And so I thought, what do I give my friend to mark this occasion? What do I give? After much thought, I decided, this is what I give:..." There followed a dramatic pause where I pressed the "up" control on the remote, and nothing happened, whereupon I muttered, appropriately enough, "Fuck", then wandered over behind my friend's chair, repeated the setup line, pressed the remote button, at which point the copter shot up, banged into a chair and fell to the ground, whereupon for my third attempt I just picked it up and held it on the palm of my hand, pressed the remote, and the copter took flight and finally delivered the punch line, and all was good. If I'm there when he re-gifts it (since we both agreed that was the point of a gift like this), I hope it works better for him.

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Falling Sand Sculptures
$13 for the smaller 'Sandscape'; $80 for the larger 'Deep Sea Round'; both available from Educational Innovations

These both make good decorations and shelf widgets. The sand in the Sandscape always falls in more or less the same pattern, since it's pre-determined by the gaps in the shelves holding the sand; the Deep Sea Round is more interesting since the pattern is determined by the placement of air bubbles and varies every time.

Pro tip: water evaporates from both of these, so eventually the water level will drop and the volume of air will increase, getting in the way of the sand flow. The 'Deep Sea Round' comes with a syringe that you can use to draw out air and inject more water into the aperture on the side. The cheaper 'Sandscape' doesn't come with a syringe, but it has a hole in the side where you can use a syringe to inject more water, if you buy the syringe separately.

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Galileo Thermometer
$17 for a wood-mounted model from Office Playground; cheaper ones available without wood mounting

Just your basic elegant conversation piece demonstrating the principle that the density of a liquid changes with temperature. Pro tip: If you get the wood mounted one, before emailing the seller to complain that it's not working because all the spheres are bunched together at the wrong end, make sure it's not upside-down. (I realized, before I hit Send, that the felt-covered end goes on the bottom.)

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All of the remaining items on this list do exactly what they say they do, with no need for any special instructions not included by the manufacturer, so I'm just going to list them:

Glass Water Faucet — $50 from Uncommon Goods — a nice double optical illusion (faucet suspended in space, and glass-as-water).

Slicked Grandfather Clock — $30-$60 depending on who's selling it.

Tin Can Robot Kit — about $15 from various vendors — my stepdad and I assembled one using one of his beloved Hansen's soda cans.

Mini metal DIY sculptures — the Metal Works sculptures from Innovatoys ($7-$12) take some time to assemble but they come out looking pretty much like the pictures and make good shelf decorations. These Mikro sculptures ($10 and up, also available from Grand Illusions if you're filling your shopping cart there) are a bit easier to assemble since you just have to bend some shapes out from the metal sheet that they're carved from.

Ulexite "Television Stones" — $10 from Educational Innovations — a naturally occuring rock containing thousands of parallel fiber optic strands. Give it as a gift together with a square of patterned fabric so you can see the eerie effect when you place the rock against the fabric and the pattern "magically" appears on the opposite side of the rock.

And finally, if you need a last-minute gag gift for someone, browse through the gum and hand sanitizers from BlueQ.com — they're not geek-themed, but at $5.49 for the hand sanitizers and $1.39 for the gum, you can afford to stock up so you'll have a reserve of gag gifts suited for a variety of different people's tastes (except, of course, good taste).

And those are my favorites for gift-giving season 2012. You can send me suggestions for any items in this category that I've missed; I'll be back for Valentine's Day.

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Remember, if you have a feature idea, we'd love to hear it.