This is very cool and I hope to see it when it's complete.
BTW, have you thought of making the values in the code samples scrubbable? (e.g. at 4:20 in this Bret Victor video http://vimeo.com/36579366). I think that that change would really aid in "feeling" the behavior of the algorithms.
Great idea for a book. I am all for interactive education. Well done. Also, what a brilliant video. A new way to interface with code and imagine algorithms, animations and data. All to be used for education! My favorite part of the video was at 30min, where Bret demos how to interactively make animations. Reading the comments on the video led me to purchasing Braid http://braid-game.com/, a game that was mentioned. HA.
EDIT: Exploring your link, I discovered Bret Victor. Anyone looking for some inspiration look at his show reel. http://worrydream.com/#!/Showreel2012
BTW, have you thought of making the values in the code samples scrubbable? (e.g. at 4:20 in this Bret Victor video http://vimeo.com/36579366). I think that that change would really aid in "feeling" the behavior of the algorithms.