No, it doesn't; it runs out. See for yourself with this hourglass full of iron filings. The steel base has a magnet, so time flies when the glass is on it, and the filings make pretty stalagmites. Stick a magnet on the neck, however, and you can stop time altogether. Glass is 5-1/2" tall on the base and filings run out in about 40 seconds (three trips make a two-minute egg) with the magnet, somewhat longer without it.

Spin this spindle and watch it turn in perpetuity!!  Well, for a long time anyway.  Inside the 5-1/2" long colored plastic spindle are magnets which are repelled by magnets in the 5" x 3" black plastic base.  The variously colored spindle floats in the air above the base thus virtually free of normal friction. Nifty desk toy named "Revolution".

Please note #91664 with flashing red lights was incorrectly advertised, that item is not available. 

A real desktop mesmerizer. This 7"x 5" moving sand sculpture creates endless sand-dune vistas, and can be so easily flipped to start over that you need never go back to actually working. The sand is so fine it's nearly liquid, and comes in varying shades, plus a little glitter. Black base and frame. We'll pick sand in shades of orange, purple, green or red for you.

Newtonian demonstrator for science teachers. Mindless play for the rest of us. These are shiny, nicely balanced, high-performance examples of the classic Newton's Cradle - a ball on one end of a row of (5) suspended, barely touching balls swings into the others, and the ball at the opposite end reacts to the collision. The 11/16" dia balls in the small version (all-metal frame 6-1/2" high x 4" x 4-1/4") will collide about 30 times. The 7/8" dia balls in the large version (metal frame 5-1/4" high x 4" x 6", with a wooden base) will collide about 100 times. Awesome. Even more awesome that we paid someone to count the bounces just for you! (Unpacking note: Less awesome if you just yank it out by the suspension lines and pull a couple of balls loose. Be gentle.)

Yes, your desktop is made of atoms (you, too) but this is a 7" dia chrome and black model of an atomic structure (Boronish, Paul says) that keeps on turning via the magic of electromagnetics, at least until the 9V battery you put in it wears out. Stands approx 9" tall on its base.  Ignore that "perpetual motion" on the box, unless you have a perpetual battery. Minimal assembly required, but a maximum person like you won't have a problem with it.

Our each is one dozen gorgeous, glimmering glass gems, in a round cut in (12) different colors, including pink, green, blue, red, golden, white, and various shades of each. Think diamond, ruby, sapphire, emerald, amethyst, topaz, whatever. In dark blue book-like presentation boxes. You pick the Princess Pack, with (12) gems at 20mm across (approx 3/4” or a tad bigger than a nickel) by 13mm (approx 1/2”) deep, or the Queen collection at 40mm across (approx 1-1/2” or tad bigger than a silver dollar) by 27mm (approx 1”) deep.

Bigger than a baseball across the top, this is one ginormous jewel. You pick a clear or deep-translucent-blue, 24% lead crystal, cut-glass gem. It’s 3-1/8” dia at the top, tapering to point 2-1/8” deep. Could be mounted in a stunning, but really, really, really big engagement ring.

You've seen everybody's favorite desk toy. The one that makes you swear you can pick up the coin that's right inside it. Too bad it's really a hologram you're looking at! Now you can own this petite version of the popular "illusion" toy. This one, 6" dia x 2" tall, with a 1-5/8" opening on the top, leaves more money in your wallet and more room on your desktop. And try to touch that little rubber frog that comes with it. It's either enchanting - or enchanted!

Well, if you had a crystal ball, you'd be able to see that there's a crystal ball in your future, and you'd know not to pass up this very, very nice glass gazing ball. It's 4-1/4" dia (and heavy) and comes with a footed dark-wood stand that spins smoothly. The stand is just over 3" dia. Together, the ball and stand are 6-1/4" tall. Comes in a presentation and storage box. The perfect accessory for your next fortune-telling gig.

Time was, these service bells were on every teacher's desk and the front desk of every hotel in the world. They're still a classically beautiful design, and they'll still bring folks running when you tap the little plunger on top. The shiny matte chrome bell sits on an enameled steel base and the whole thing is 3-1/8" dia x 2-1/4" tall.