This site contains challenging and intriguing math problems and puzzles.
Many options are available by following the navigational tools.
The rec.puzzles archive is a list of puzzles, categorized by subject area. Each puzzle includes a solution, compiled from various sources. Categories include analogies, cryptology, logic, riddles, trivia, and many, many more. It will serve as a forum to exchange views, opinions, comments, and suggestions about the wider world of puzzles and intriguing mental challenge. Fun for the whole family.