Seems to be a fair number of BJJ practitioners here. It comes up in most threads on fitness/exercise. I've only just started (6 months now), mostly as a way to force myself to really exercise regularly. Having a positive social environment and forking out $$ each month encourages me to actually attend, versus the (good) free gym available through work.

EDIT: If you really want to know it could be put in as a poll. Ask which martial arts (if any) people here participate in.