I was on the bid selection committee for Wikimania 2007 and Wikimania 2008, because of being a past organizer; the bid jury helps pick a conference location out of the bidding cities. For the bid juries for Wikimania 2009 and Wikimania 2010, I was the jury moderator, which means I didn't vote but did try to wrangle people into consensus, ran lots of meetings, etc.; for Wikimania 2011 and 2012, I am a non-voting jury advisor.
I have also presented or moderated at all five Wikimanias:
Wikimania 2005: I gave a talk on user impressions of Wikipedia, based on a small qualitative study I did at UW
Wikimania 2006: With James Forrester, I ran an open discussion about research in Wikipedia
Wikimania 2007: I moderated several rounds of lightning talks and some other talks
Wikimania 2008: I co-organized and participated in a panel about libraries and Wikipedia; and I ran a rather silly but quite successful workshop about making sockpuppets
Wikimania 2009: I am hoping to run a couple of open discussions about community meetups