At Wikimania 2010, there was a Trivia Night (see the slides).
You had to team with at most 3 other people. And you get +1 point for each right answer.
Some of the question were:
* Is this a Wikipedia article?
* [[The Smurfs and communism]]
* [[Exploding head syndrome]]
* [[Martian language]]
* [[Death from laughing]]
* [[AOL disk collecting]]
* [[Lawn mower racing]]
* [[[[Vampire pumpkins and watermelons]].
Great simple idea for warming up the conference in a light way. Should have been fun ;)