See also:

• Science: Math: Recreations: Games and Puzzles  (75)

• CellFighter - Shareware game based around an extension of the game of life.
• IBM Research: Ponder This - Monthly logic and math puzzles set by IBM researchers with solutions.
• Jim Loy's Puzzle Page - Classic and original puzzles.
• Kakuro-san - Providing graded Kakuro puzzles every day, plus old puzzles.
• Leisure Ideas: Puzzles - Some mathematical puzzles with answers and/or a hint.
• Mathematical Jigsaw Puzzles - Information on polyominos and square puzzles.
• Monty Hall Game - JavaScript example of the Monty Hall Game. This game demonstrates the real (empirical) affect of statistics. [Does not display correctly in all browsers.]
• The Monty Hall Problem - A probability theory puzzle with solutions. [English and German.]
• Perplexus - A forum and collection of brain teasers, logic problems, math problems, paradoxes, science games, probability, riddles, and geometric shapes. The puzzles are searchable and categorized, most have solutions.
• The Puzzles of Oscar - Contains puzzles and games with solutions.
• Quick Logic Puzzles - Use the clues provided to deduce the correct sequence of numbers in the hidden code.
• TechInterview - Answers to technical interview questions, programming problems, and brain teasers.
• The Truth Tree's Math and Logic Board - Collection of math and logic puzzles ranging in levels of difficulty.
• Two Envelope Paradox - Solution - Claims that the two envelope paradox comes from the incorrect use of probabilities.
• WU Forums - Discussion board hosted at Berkeley with talk about a variety of solved and unsolved brain teasers.