I've added a second video to my post about Government 2.0 Camp (and a third below, as you can see). The second one, located in March 31 post, shows people in the audience standing up and suggesting session topics for that day. Nevermind if you can't hear every word spoken. The video will give you a sense of how the agenda for the day gets set at a "barcamp."
The clip below is one of the posters that appeared at the conference. An "artist-in-residence" was drawing them each day to reflect the activities underway.