Where Can You Obtain Surplus Mechanical Parts?

Brian Craft asks: "When I was in Pasadena all the nerds with an inclination toward building Electronic-Things-That-Move would go to this place called C&H, on Colorado Blvd. It was a wacky surplus store where you could buy everything from worm gears, to stepper motors, pulleys, power supplies, 20 turn pots, and used passenger jet windows (no joke!), for very, very little money. I'm now up north, a bit south of the Bay, and I haven't found anyplace as cool as C&H. There seem to be computer and electronic surplus stores on every corner. But where do you go when you need to browse piles of gears to find one that fits the worm gear on your stepper motor? When you need small bearings, or pulleys, or solenoids? Or just the sight of lots and lots of really cool mechanical stuff, to inspire your next project?" Are there any cool surplus stores in your area or online? If so, share them here!