django-markdownx (Comprehensive Markdown plugin built for Django)
Python-Markdown (A Python implementation of John Gruber’s Markdown with Extension support)
See also
https://github.com/trentm/python-markdown2
https://twitter.com/trentmick
https://github.com/trentm/python-markdown2/wiki
https://github.com/trentm/python-markdown2/wiki/Extras