Here is a time lapse overview (silent) of our first jam session at home. Fifteen friends, all non musicians but two amateur musicians, joined the machines set in turn, around 8 at a time, to improvise electro or hip-hop rhythmic grooves. Of course there were food and drinks too!
The goal was to introduce music making in an attractive way: no pressure, no constraint, no reason to be shy, just have fun!
More at: http://cyrille.martraire.com/2009/05/jam-session-at-home