Another event that has came across my radar this morning is
Wikipedia Academy: Research and Free Knowledge. It will take play
June 29 - July 1 in...Berlin!
"
The “Wikipedia Academy 2012: Research and Free Knowledge” provides a
platform for the research community and the Wikipedia community to
connect, present, discuss and advance research on Wikipedia in
particular and on free knowledge in general."
The call for papers has been extended until April 15.