Gource is a famous version control visualization tool, supports git, svn, hg, bzr and cvs2cl, I tried to use gource to visualize the CDNJS development history, and here are the videos I uploaded to youtube.
CDNJS main repository:
(https://github.com/cdnjs/cdnjs)
CDNJS new-website repository:
(https://github.com/cdnjs/new-website)