I think puzzles capture the essence of math and the scientific method. Sometimes it requires very logical steps and other times it involves lateral out-of-the-box thinking. I love to see students, especially those with an aversion to math, get into the fun and freedom of a puzzle.
I use math to encourage this kind of thinking but also to reduce the math anxiety that is so prevalent in our society. Everyone enjoys a game, but puzzles are non-competitive and allow for everyone to win. Here are some great resources for games to enjoy with your students.
Sudoku - Fill in all of the numbers from 1-9 horizontally, vertically, and in the box. Extremely popular. Play online or print out for class or home.
Kakuro/KenKen - Like Sudoku but with an added twist, the numbers inside a "cage" must add up to a certain total. Great for building number sense. I actually had a student shocked that they were enjoying math so much (she said she was addicted to the puzzles)!
Dr. Math @ Drexel - From the famous to the obscure, I put up a problem from here every week to challenge my students. Problems of all levels and abilities are available and it is also an excellent resource for math help that students can submit their own questions.
Math Games - Broad assortment of casual games for class or at home with family. If you can get the family to enjoy math and encourage it at home, it is a proven fact their student will be more interested and stronger in their math skills.
Mr. L's Math - Already mentioned this in a previous blog post. Great ideas for a classroom filled with math and fun. Teacher to Teacher Press has some materials for sale which are well worth it.
Ken's Puzzle of the Week - While the site is no longer being updated, there are still many great puzzles to enjoy.
University of Idaho Math Challenge - No longer updated, but another great resource for fun mathematical brain teasers.
East of The Web - General grouping of word puzzles.
Merriam Webster - The popular dictionary provides crosswords, scrambles, and word searches.
Scrabble - Play the popular game online
Word Games - This site touts itself as the place for the most popular word games.
General Puzzle Sites:
These sites include your riddles, math puzzles, visual, and otherwise.
Optical Illusions - This site is just too good to leave out of a thought provoking post like this. They will blow your mind and your students will not believe their eyes.
Do you have another great site? List it in the comments below.