The nice folks over at IPython have put together a nice viewer for IPython notebooks stored as GitHub gists: nbviewer.ipython.org/. Just enter a gist URL or number. It doesn’t actually store notebooks, just renders notebooks stored as gists.
I’ve had some notebooks as gists for a while and now I can make pretty links to them:
Pen and Pants 
[…] a few months now I’ve been using the IPython Notebook as my primary teaching tool for Python topics. Within Software Carpentry we’re also switching over to using the Notebook for both […]