Just did a race at the Nor-Cal Hobbies off road track in Union City, California.
AWESOME!
My brother and I brought our 4wd 1/10 buggies over from the UK to the SF Bay Area since were were visiting the family and we came down to the track for some practice and a race.
It was encouraging to meet such friendly people both as racers as well as shop staff. The track was also in good form and we had a sweet time for sure.
VERY different racing on sugared dirt compared to what we're used to in the UK, but it was cool to do something different.
Anyhow - the track and the shop are highly recommended. They have four tracks on site - a mega offroad track (with both 1/10 and 1/8 layouts), a clay oval, an outdoor onroad track, and an indoor carpet track.
http://www.norcal-hobbies.com/