Norcal Hobbies (Union City CA.)- Races 1/10th & 1/8th off-road every weekend year round (except when it's raining hard). Alternating between Sat & Sun. Plus a couple of big race weekends. They also race 1/10th & 1/12th on-road every week(weather permitting outside & on the carpet inside). Their schedule can be found at rcracing.com in the race schedule area.
http://www.rcracing.com/Race_Schedule_284.cfm
This is primarily electric but they have semi regular Nitro on-road (1/10th) & are starting a Nitro off-road program (1/8th) very soon (just put in the pit lane).