This is incredibly well done! I happen to love lightweight markup languages like this, so the fact that you're using one makes it irresistible.

To the authors: you said you used Jison[^1] to parse the text. Did you use any external resources to familiarize yourself with its syntax?

EDIT: It looks like Udacity has a series of videos that touch on it: http://www.youtube.com/user/Udacity/videos?query=CS262+

[1]: http://zaach.github.com/jison/