Yesterday afternoon, while out enjoying the sunshine, I went down to Borders to shop around for some cool books and found more than a couple. One in particular is a book titled "Flash Math Creativity" which looks very promising for getting up to speed with some very cool Flash math projects. The book is the culmination of contributions from about a dozen artists, thereby providing a rich diversity of interest and approach. The book was more money than I had on me, though I found the web site referenced in the book with all the source code. =)
The web site has all of the examples from the book, and most of them are really spectacular and interactive. And if you get bored with those, there are links to each of the contributors' web sites offering even more to explore.
One contributor, Manuel Tan, keeps a personal site that is especially impressive in interactive design, uncontrol. There he offers everything open source for anyone wishing to learn about the underlying code.