The Museum of Unworkable Decives

For thousands of years humans have dreamed of creating a perpetual motion machine, a machine that could do useful work while functioning without any sort of input forever. Science says that this is impossible, but that hasn't stopped people from trying. The Museum of Unworkable Devices has extensive information on perpetual motion machines past and present, as well as detailed scientific explanations on why they won't work. It also has some optical illusions, and a few drawings by Escher and the like. Check it out.