The WikiForum, based on WardsOriginalWikiEngine, can be entered via http://c2.com/cgi/wiki.
Sometimes it is referred as WikiWikiWeb, not differentiating between the underlying engine and its forum. :)
Do I remember it right, that there was another forum on the site of WardCunningham, also based on WardsOriginalWikiEngine? Something on SystemTheory. -- FridemarPache