If you've been to an Arizona Roller Derby or Arizona Derby Dames match, you've seen Joker. Or heard her. She's the chick with the glasses and curly Mohawk who positions herself behind a team bench or right out on the rink, screaming her head off. Sometimes, she's dressed in the colors of a particular team (with face paint to match), and other times, she's just wearing buttons or T-shirts that proclaim her team spirit. But no matter how she's dressed, she always acts the same — she'll scream at refs for "bad calls," shout encouragement at players, and slam her fists against the rink floor or bench ledge. Since the local roller derby leagues were founded more than five years ago, Joker's rarely missed a match in either league, and she can recall incidents from games five years ago with all the clarity of a fan who's watched the same footage over and over. She's even made her way into video clips of the Arizona Derby Dames, by virtue of just always being around. And though roller derby has its share of devout fans here, none of them is as enthusiastic and downright lusty as Joker. For her, even seeing the Derby Dames selling brownies outside Bikini Lounge on First Friday qualifies as an event.