Open PLAN Workshop
Take a dozen smart & creative people, normally independent, vaguely around the same interest area. Place them in a room in Nottingham for a week, feed and (fire)water regularly, and poke & prod to some brilliant ideas emerge on the other side. It was pretty enjoyable!
Participants included an artist who built interactive algorithmic audio doors in China, a designer of Swedish live action role playing weekends, mobile device phreaks, geo and rdf hackers, and a geometry professor.