Puzzles and Games

• KenKen Math Puzzles
• Puzzle PLAYGROUND
• John Conway's Game of Life
• Mathpuzzle.com
• Rubik's Online
• Aha Puzzles!
• Brain Teasers by Barry R. Clarke 
• Sliding Block Puzzle Page
• The Diamond 16 Puzzle
• Combinatorial Games 
• Puzzles with polyhedra and numbers
• Nick's Mathematical Puzzles

Pythagorean Pages

• It Is Wise, Generalize!: Mathematics & Informatics Quarterly by K. R. S. Sastry
• Expansion/Analysis of a Card Trick: Math Paths by Aaron Kazam Sherbany
• Exploring: Moduli Spaces by Jordan Ellenberg
• An Interesting Diophantine Equation: Mathematics & Informatics Quarterly by G. Greaves and J. Rigby
• Sylvester's Problem: Prove It by Nathaniel Watson
• The Buffon Needle Problem: Yesterday by Prof. Paul Goodey
• Spinning Egg Riddle Not All It's Cracked Up To Be: Today by Sarah Potter
• Hailstones, Bracelets, and Kaprekar's Constant: Math Paths by Don Allen
• The Elegant Universe by Brian Greene: Book Rave by Richard Rusczyk
• The Sum of the First n Positive Odd Integers: Seeing is Believing by Richard Rusczyk