Nutshell Math These are YouTube videos of over 50 math lessons.
CTAP 4: Math Projects - standards based and peer critiqued lessons to use in your math classroom.
National Library of Virtual Manipulatives This site is FANTASTIC! Check it out.
AAA Math This is a very well organized site with tutorials, games and practice areas.
Brain Den This site has geometry and algebra puzzles as well as other teasers and puzzles. Make sure to scroll down as the ads at the top can be discouraging.
Eduplace Houghton Mifflin 's Math Brain Teaser site. Includes a weekly question.
BrainBashers Puzzles and surveys for kids. This site includes soduku and other math puzzles.
Lemonade Stand This is an old classic designed to teach kids supply and demand concepts. In the game the player decides how many supplies to purchase for his or her lemonade stand. The player is given variables regarding weather conditions and temperature. Then the player goes through a simulation day to see how well his or her supplies held up to the demand of the lemonade drinkers.
California Mathematics State Standards We already have these, of course, but sometimes it's nice to be able to access them from the web.