LocalWiki is one of the nicest open source wiki engines around, what with the WYSIWYG editor and all. I look forward to the core version mentioned in the FAQ, although I can live with maps functionality baked in in the meantime.
LocalWiki is a Django-based mostly Python project.
There's a link on that page right there ("get the code") as well as the "fork me on github" banner in the main site. Should we make this more clear? (not sure if you were pointing out a deficiency or asking a question)