Chess boxing is a sport most people have never heard of. Competitors alternate rounds of chess and boxing and win by knockout or by checkmate, whichever happens first. Even the players admit that they doubted the sport was real when they first heard about it. “I thought it was, like a ‘Saturday Night Live’ skit. It was so absurd to me that someone would combine these two things,” says Matt Thomas, a chess boxing world champion. | 60 Minutes