This is an amazing online maths playground with a huge number of tools to help learn and demonstrate every area of maths. Create animations and even embed videos.
http://ictmagic.wikispaces.com/maths
My kids love to do the science fair, but every year they are stumped as to what projects to pursue. This site has terrific ideas, presented in kid-friendly language/design...so when science fair season rolls around I'll be showing them this site.