You've done it thousands of times. After a game-winning shot, a solid joke, a perfectly executed parallel parking job. You've probably never thought twice about who did it first. The high-five is so woven into sports and everyday life that it feels like it must have existed forever - like a handshake or a wave. It hasn't. The high-five is a surprisingly modern gesture, and its exact origin is one of the more entertaining unsettled debates in sports.