The Linux Users' Group of Davis (LUGOD), a computer club for Linux and free & open source software users and based in Davis, California, serves not just the community of Davis and students, faculty and staff at UC Davis, but is one of only two active LUGs in the region. (As of June 2010; the other being SacLUG.)
Davis is situated in Yolo County, and near Solano County and Sacramento County. It's also only a 1- to 2-hours drive from many points in the greater San Francisco Bay Area and Silicon Valley.
Towns and cities near Davis (many from which we've seen meeting attendees), include:
And, of course, it's possible to interact with LUGOD and its members over the Internet: