The more people who participate in a jam, the more fun. One easy way to get more people on stage is to have a supply of hand percussion instruments: maracas, tambourine, mini cymbals, castanets, guiro (my personal favorite), and of course, cowbells. Plus, many of these instruments really do require ...
Started a JAMFEST BLOG a while back - http://www.bobbaehr.com/jamfest2008.nsf
I have 2 confirmed for "Comfortably Numb" by Pink Floyd. Still need another guitar, bass, keyboards, vocals, and of course -- the eternal cowbell.