Bateria Lucha is a Bay Area percussion ensemble, an activist group and a Drupal website.  All three things which rank high on my recommendation list, and while I've known of them for several years, I only finally attended some of their classes recently.

Wow.  Bateria Lucha freakin' rocks!  They have open rehearsals / classes - and anyone can come and join, even absolute beginners (check their site for details).  There is a big focus on maracatu rhtyhms (YouTube link), from Northeastern Brazil, which have unusual syncopation for those used to the samba world of Brazilian music.

Note:  Bateria Lucha's classes / rehearsals are in flux right now, as they try out some new spaces.  Best thing is to go to the site, register for an account and get on their email list.  Hopefully within the next few weeks they will have a permanent rehearsal space - otherwise, you can look forward to playing drums in the park, near the soccer pitches (what is more perfect anyway?).

And who knows - you may see me there....