Hula-hoops may seem an unlikely vehicle for social change, but the hardcore hoopers behind World Hoop Day use the circular playthings for the forces of good, donating hoops to underprivileged kids in Haiti, Sri Lanka, and other impoverished communities where playtime and toys are scarce. Led by Annie O'Keeffe, some of hula's biggest local enthusiasts (including the HoopGirl Allstars) celebrate their love for the sport and raise awareness of their cause. The daylong event features hip-swiveling performances, lessons, giveaways, and music.