Mad Math Minute -- Addition Practice http://www.softschools.com/math/games/mad_minute_math/
Alien Addition and Subtraction http://www.4kids.org/games/
White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Ask Jeeves for Kids! The fastest and easiest place for children to get answers on-line. http://www.ajkids.com
Practice grammar and spelling http://www.factmonster.com/ipka/A0882902.html
Try an Everyday Math game! http://www.emgames.com
Discovery for Kids http://kids.discovery.com/
Try some fun games for your brain! http://www.funbrain.com