Garbage + illumination = art? Various artists carefully pile rubbish on a gallery floor, or meticulously assemble a collection of ordinary items, plug in a light source, and create incredibly detailed and surprising shadows on the wall. Meanwhile, blog commenters cry "Fake!" and "Photoshop!". I guess they didn't see any of the Quicktime movies of Shigeo Fukuda linked here.
The sculptures of Shigeo Fukuda show that shadows and reflections (mpegs) may not be what they appear to be. When you turn M.C. Escher's drawings into sculptures, you can get some impossible objects (mpeg). And Dick Termes paintings on globes are stunning examples (Quicktime) of six point perspective. All of these works of illusionary art are featured in the book Masters of Deception: Escher, Dalí & the Artists of Optical Illusion and must be seen to be believed.