Puzzles and mathematical recreations
Like most Science students, I find fascinating the ingenuity that lies beneath the, in many cases deceptively simple, puzzles and mathematical recreations. Here I have collected some with pointers to many more.
Links
M. C. Escher: The mathematical artist par excellence, even if not on purpose.
Interactive mathematics miscellany and puzzles: A. Bogolmony mantains this site which contains many nice (and interactive!) mathematical puzzles.
Thinkfun: An on-line shop with many kinds of puzzles and brainsteasers, and some on-line games.