Funbrain http://www.funbrain.com/
Games & Contests http://www.scholastic.com/kids/games.htm
Yahooligan Games http://www.yahooligans.com/content/games/
Quia http://www.quia.com/web
World Almanac Games http://www.worldalmanacforkids.com/fun-games/index.html
Kids Place Games http://www.eduplace.com/kids/index.html
Scholastic Games & Quizzes http://teacher.scholastic.com/scholasticnews/games_quizzes/index.asp