Educational Games

http://discoverylake.discoveryeducation.com/ Thrill of the Catch - create and feed your fish as well as become an angler Outdoor recreation  
http://www.sporcle.com/games/ Thousands of free online trivia quizzes about geography, movies, science and more All
http://akidsmath.com/mathgames/index.html A Kid's Math Math
http://hoodamath.com/games/ Math games, math help, math worksheets related sites, aligned with NCTM Math  
http://coolmath.com/ Math games and puzzles, lots of really clear math lessons (arithmetic, fractions, decimals, algebra, etc. Math  
http://mathisfun.com/ Math explained in easy language, plus puzzles, games, quizzes, worksheets and a forum. K-12 Math
http://edheads.org/ Non-profit organization that provides free high quality educational activities Science
http://www.ilike2learn.com/ Interactive geography quizzes for countries and capitals Social Studies  
http://www.freerice.com/index.php a site that is battling world hunger while helping students learn vocabulary  Vocabulary, English
http://hoodaword.com/games Reading, typing, word games Vocabulary, English
http://quiz.history.com/quiz Ultimate History Quiz History