Hello,
I would like to do something along the lines of: http://twitter.github.com/bootstrap/customize.html
People could select the components they want to download.
Could someone point me in the right direction?
Regards,
-jj. 
The front end, at least, is all JS. Guts of the app are at http://twitter.github.com/bootstrap/assets/js/application.js.
Now, what happens at http://bootstrap.herokuapp.com is a more interesting question.