Aims Puzzle Center
The AIMS Puzzle Corner provides over 100 interesting puzzles that can help students learn to enjoy puzzles and the mathematics behind them. The puzzles are categorized by type, and within each category are listed in order of increasing difficulty. The puzzles have have not been assigned a grade level appropriateness because the ability to do a puzzle varies by individual not grade level.
http://www.aimsedu.org/puzzle/index.html Brain Quest
Brain Quest challenges kids on the stuff you need to know, when you need to know it. All you need to do is answer as many questions as you can, as quickly as possible. Don"t forget to post your score and challenge a friend! Good luck!
Interactive chess lessons, quizzes, games and puzzles
http://www.chesskids.com/ The Exploratorium"s Online Exhibits
Online optical illusions
http://www.exploratorium.edu/exhibits/f_exhibits.html Family Puzzles
Exercise for Brains of all ages. Great fun for the entire family. Just click the graphic for the puzzle you"d like to try.
http://www.teachersandfamilies.com/open/puzzle/ Jigsaw Puzzles
JigZone is an online Jigsaw Puzzle where you choose the level of difficulty from a simple 6 piece cut to a challenging 247 piece cut.
Online trivia quiz site.
http://www.triviaplaza.com/ The Ultimate Puzzle Site
This collection of puzzles, riddles, brainteasers, and interactive tests challenges students to think outside of the box and improve their analytical skills while having fun. Puzzles are graded by level of difficulty and the amount of math needed to arrive at a solution.
http://puzzle.dse.nl/index_us.html Web SuDoKu
An online number placing games. Each Sudoku has a unique solution that can be reached logically without guessing.