A blonde in a uniform, wearing a helmet with a star on either side, puts on a serious face. A whistle blows; a pack of women from a competing group tries to keep her back. The jammer, though, is not fucking around. Get in her way, and she'll muscle right past you, and if you fall, well, don't you dare cry. This is roller derby, Orange County's best cheap night out: no frills, bench seating, surprisingly great snacks, and mild-mannered professional women getting fierce on a banked track in Santa Ana. Once they're off the rink, though, smiles abound; spectators and skaters make plans to party together. Keep that serious face in mind, though.