There are many that seem to be in progress. Not mentioned on the
Django wiki [1] is DjangoBB [2].
The quality and functionality seem to vary wildly. Ultimately I
decided to write my own. With the tools that Django provides, it
really isn't that hard (much to my surprise). I wanted some features
that the other projects didn't have, but more importantly I want to
know how it works, and for my hobby site, rolling my own was the best
course of action for me. YMMW of course.
[1]
http://code.djangoproject.com/wiki/ForumAppsComparison
[2]
http://djangobb.org/