I just heard about this recently on the GeeksOn podcast. Chessboxing. Do you believe it? Yeah. Four minute chess rounds, then two minute boxing rounds. You can win by checkmate, knockout, or running out of time on the chess clock.
I found a YouTube video of the chess boxing world championship. Yep. There's a WCBO. It's really weird to see a guy breathing hard at a chess table. Check out the video.