Coolmath.com by Karen (http://www.coolmath.com/)
A self-proclaimed amusement park of mathematics.  Those learning pre-algebra, algebra, geometry or calculus will find this site fun and helpful. Teacher links for a variety of math students levels as well.

Math Advantage (http://www.harcourtschool.com/menus/math_advantage.html)
Choose your grade, then choose your game. This site, brought to you by Harcourt Brace, reflects certain topics from the textbook of that grade in game format.

Learning Wave Communications (http://www.learningwave.com/engage/index.html)
Middle School math teachers--pay attention. Your students will love this site as they use math skills in AbsurdMath, The Bad Cashier and Geometry of the Ancients. Check it out and enjoy yourself!

Flashcards for Kids (http://edu4kids.com/math/)
Choose the math concept to be practiced as well as the level of difficulty, then practice. Very easy to use!

BrainPop (http://www.brainpop.com/)
Watch entertaining and educational animated cartoons, which explain many scientific things, such as how your eyes work, what a water cycle is, and how your digestion system works. You can also try some experiments with "Bob, the Ex-lab Rat" or ask questions of your own.

Science for Families (http://scienceforfamilies.allinfo-about.com/)
All sorts of great science links. A new article and feature each week.

Teach R Kids Math (http://www.teachrkids.com/)
This interactive site will help your child learn key mathematical concepts.