Turn a Pringles can into a camera
By way of Gizmodo.com: A website showing how to turn an empty can of Pringles potato chips into a pinhole camera. For those who don't know, the pinhole theory is how cellphone cameras work as well - it takes a little science to explain fully, but basically if a camera's aperture is small enough (like the hole a stickpin produces in a piece of aluminum foil, for example), then the depth of field for that camera nears infinity, meaning that you don't need a focus knob for the "lens" (the pinhole).
Anyway, the directions for building one are at that site, but much more interesting are the actual images the author (Rowena Dugdale) took with her own, and has posted to the site. They're incredibly creepy and cool, like something out of a David Fincher movie; the mere fact that I could take creepy photos like them myself makes me want to build one!