Though the sport is getting more organized, the vast majority of play is still in grassroots, unofficial pickup games. A catch in the end zone scores a point. Incomplete passes cause the disc to change hands, and the defense becomes the offense. Perhaps most radical, there are no refs, although some tournaments employ observers who judge appeals. Otherwise, players call fouls.
Intentional contact is taboo.
But for a noncontact sport, it's pretty rough. Sprains and dislocations are fairly common, and the constant changing of direction means knees are at risk, too. A 12-year veteran of various San Francisco Bay Area teams, Corinne's had five knee surgeries due to her Ultimate passion. Unlike pro sports, nobody's paying these disc hurlers. But even without hope of a big payday, Ultimate players may travel to as many as ten tournaments a year on their own dimes, cramming vans and crashing couches.