Some people wouldn't know disc golf from a hole in the ground, but the PDGA does. The Professional Disc Golf Association (PDGA) promotes the sport of disc golf, a game played with specially designed flying discs and baskets, rather than dimpled balls and holes. Founded in 1976, the PDGA sanctions about 550 annual amateur and professional competitions (including championship events) and boasts more than 16,000 members in about 20 countries. The sport has seen rapid growth, from one course in 1975 to more than 2,500 today. The vast majority of disc golf courses are in the US.