I’ve been running a martial arts class under the Jeet Kune Do banner for about eight years now.
The class is free, but you do need to sign up for it through meetup.com. I’m mostly friendly. It’s geared more towards the curiosity seekers than the hardened veterans of MMA, though I do get those too. The idea is and remains to offer an open and safe exchange of ideas in a way that is difficult in the commercial classes.
I run it in the Golden Gate Park on the Weekends, for time and location, look here.