I had a great experience this past Saturday attending the Austin Flixel Jam, an "indie game jam" where about ~11 guys met up to make a game in one day - specifically 6.5 hours (which is as long as the library would let us work in one of their offices).
I showed up knowing no one, with no idea what to expect - a true "dive in headfirst" scenario. I met the host, Phil Knoll, a very cool guy, and chatted with him about my experiences at Blizzard and SOE - small world, he's indirectly done some outsourcing projects for SOE Austin and knows a couple of my friends there.
Finally some more guys showed up and we began talking about what we were going to do. I had expected that Phil, the organizer, might have had some pet idea already picked out; and that every single guy who showed up would probably have their own ideas as well... in short I expected something of a fight over who would get to make their game idea! Instead something very different happen: Phil mentioned that he thought we should make a game like Canabalt (the most well-known game made in the Flixel engine we were using). In particular we all felt the idea of a "single button" game seemed ideal.