A Plus Math http://www.aplusmath.com/Flashcards/addition.html
Math Magician http://oswego.org/ocsd-web/games/mathmagician/maths1.html
Spelling City http://www.spellingcity.com
Stop the Clock http://resources.oswego.org/games/StopTheClock/sthec3.html
Online Math Games http://www.sheppardsoftware.com/math.htm