Scratch is a wonderful project out of the wonderful school, MIT, the Massachusetts Institute of Technology. This project is designed to allow children of all ages to learn the basics of programming by hiding the language, and structure of programming behind pretty pictures, called sprites. It also makes adding sound and movement to a presentation very very easy.
So, I have put some time in and I have created demos for some of the "Properties of Real Numbers" that I teach during pre-algebra lessons and that everyone should be familiar with if they did not sleep through their 7th and 8th grade math classes. If you did, then maybe you should pop over to http://scratch.mit.edu/ and search for the distributive property, or the commutative property. Please leave a comment there if you do, and vote it up!
Math and computer programming tutor