The following are some of my favorite links. You can find games, brain teasers, and math tricks.. You can also find instruction for a variety of basic skills as well as algebra help.
Parents - many of these sites have parent links. Take some time to explore all the resources these sites have to offer.
Cool Math 4 Kids
Math Playground
AAA Math
A+ Math
Game Aquarium
SuperKids Math Worksheet Creator
Interactive Mathematics