Open Space camp/unconference on wiki and many other cool things — collaboration, community, etc. See http://recentchangescmp.org for links to each event's wiki
Next one in Portland, early 2010 (or Australia this year?)
This year (2009) Wagn was chosen as the conference wiki software — see http://2009rcc.org/
There have been Wagn Demonstrations at the 2007 & 2009 Portland and 2008 Palo Alto RecentChangesCamps. Wagn was conceived at the 2006 RCC.
Also see ImminentChangesCamp.