When you first enter Claim Jumper, you'll immediately realize that it is, in fact, a theme restaurant. The walls are formed from stone and mortar, and the ceiling fans are powered by exposed belts and gears, a sure sign of a prepackaged experience. Normally, restaurants with lots of prefabricated crap on the walls send foodies running for the streets, teary-eyed and sneer-lipped. But don't let the faux Old West interior fool you. Thursday through Sunday nights, Claim Jumper has the best prime rib available in the East Bay, and the fact that this space isn't unique doesn't make these huge slabs any less juicy. If prime rib isn't your thing, there are plenty of other cuts on the menu for the discerning carnivore.