 It's 96 degrees at Walker Park in Fayetteville, and the heat seems to have kept most people away from the baseball fields and grassy areas. But under a pavilion, more than three dozen women, men, and children are hosting a meet and greet. This is a recruitment rally for the Northwest Arkansas Roller Girls, women forming a roller derby league. Roller derby attracted television audiences in the 1950s and again in the 1970s with a high-concept blend of camp, melodrama, and roller skating.