That's the Min-Aqua Bats boat and ski show from Wisconsin - the guy still might be crazy, but it a part of the show -- similar to the trick car shows, etc.
Back in 1980,down at Clearwater Lake in southern MO, there was a guy with a bassboat,outside of the Bluffview swimbeach,that was doing the exact thing. With ONE engine. At one point, it almost when straight down into the water. I said the same thing back then,"What a Dumba$$".