I went along to one for Peace Day a bit ago. It was the most worthy cause I could think of, and a motivation to practice at a time when I wasn't so motivated (note on the way, note while sitting, note on the way back). Could be a chance to meet other practitioners too, though acute awareness of the mushroom factor stopped me trying at the time. The sound bath effect is also very pleasant and a nice ritual highlighting interdependence, if you're into that sort of thing.
