http://whatismusic.info/ the website for my book What is Music? Solving a Scientific Mystery, which explains my "super-stimulus" theory of music: the theory that music is a super-stimulus for musicality, where "musicality" is a perceived aspect of normal speech, the perception of which tells the listener something about the current mental state of the speaker. (The book is now available as a free download.)
What is Music? the issues which music science must deal with and how they relate to my theory
The Billion Dollar Puzzle a different reason
why you might be interested in solving the scientific mystery of music
How To Compose Music an attempt to develop a theory of how to compose music based on what we don't know about music.
PrimeShooterTM a Javascript 2-D shoot-em up game where you kill numbers by shooting them with their prime factors
IntegerZone a Java applet demonstrating aspects of arithmetic and number theory which uses an infinite scrollable grid of integers as its main interface
TenBlocks a Java applet for younger users which might help them to learn multiplication