Say "go pigeon!", wait a few seconds, and then let the "cat" go. The "cat" chases the pigeon around the court, when the pigeon gets tired he jumps into someone's "nest" (hoop) and releases that pigeon. Then the "cat" chases the new "pigeon". If the "cat" catches the "pigeon", they instantly swap roles and the new "cat" chases the new "pigeon".
Run fast and have fun!