So I saw the Rev a few years ago at Bumbershoot in Seattle, and I still kinda laugh about it.
They played the song called "Marijuana", and about half the crowd lit up - damn near hotboxed the venue. The next song they played was "In Your Wildest Dreams", but before they began Jim asked the crowd to do a cha-cha-cha ending with the band.
Well, after the 5 minutes of a song called Marijuana, and 5 more minutes of the next song, everyone forgot the cha-cha-cha ending.. They actually re-did the last thirty seconds of the song so people could do the cha-cha-cha ending.
Remember kids, drugs are bad.