Not Your Ordinary Book Light, A Reading Light Inside of a Gutted Book
I love this so much I might just make one.
(Source: vimeo.com)
This machine manipulates small spherical rare earth magnets, slicing one at a time from the end of a long chain, moving it around a bit, then dropping it back to re-connect at the tail end of the chain. It also demonstrates a little snippet of science called eddy currents. Watch how slowly the magnet falls through the aluminum tube compared to falling through air: the falling magnet generates an electrical current in the tube, and that current in turn generates a magnetic field that opposes the movement of the magnet, slowing it down dramatically.
Source: Marvelous Hand Cranked Machine for Rare Earth Ball Magnets, Laughing Squid