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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.

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.