Fun addition game. Get the frog to eat the answers. http://www.hungryfrog.com/java/javamath1.htm
Math games for just about any subject: try the pizza game for fractions or the graphing game. http://www.mrnussbaum.com/mathcode.htm
math baseball, roman numerals, equivalent fractions http://www.funbrain.com
fraction soccer game but not for the cowardly! You must simplify! http://www.funbrain.com/fractop/index.html
roman numeral game http://www.factmonster.com/pages/numeralgame.html
fill your piggy bank with cash, but get a question wrong and you lose money! http://www.funbrain.com/cashreg/index.html
Learn place value up to the millions and beyond if you do super- brain. http://www.funbrain.com/tens/index.html
A quick geometry game with a hidden picture. http://www.funbrain.com/poly/index.html
Division Matho! http://www.aplusmath.com/games/matho/DivMatho.html
Fractions made oh so simple! http://www.coolmath.com/fractions/fractions1.html
Fun push button flash cards. http://www.kidsnumbers.com/
Hidden pictures and practice for +,-,x,/. http://www.aplusmath.com/games/
Can you do percentages yet? http://pbskids.org/cyberchase/games.html
Balloon invaders! Practice skills and smash balloons. http://www.mathplayground.com/Balloon_Invaders.html
Geometry games with a ruler you can push around. http://www.mathplayground.com/InteractiveGeometry.html
Play "Who Wants To Be A Millionaire" for math http://www.mathplayground.com/RTW.html
Polygon matching game. Easy! http://www.mathplayground.com/Matching_Shapes.html
Fractions and percent matching for smarty pants. http://www.mathplayground.com/Matching_Fraction_Percent.html
Tangrams for fun. http://www.mathplayground.com/tangrams.html
Math munchers for multiplication. http://www.mathplayground.com/Math_Munchers.html
Symmetry made easy. http://www.mathplayground.com/Perfectly_Symmetrical.html
Figure out the value of the circle, the triangle and the square. http://www.mathplayground.com/Algebra_Puzzle.html
Zap aliens with multiplication. http://www.mathplayground.com/AlienMath.html
You figure out when you need addition and when you need multiplication. http://www.mathplayground.com/Calculator_Chaos.html
Educational reading games. Fun maze. gamegoo.com
Fun science site: design your own roller coaster and learn about force and motion. http://www.learner.org/interactives/parkphysics/
Huge bunch of math games and virtual tools. http://nlvm.usu.edu/en/nav/category_g_2_t_1.html