As Mr. Jalopy points out, there was a time when a person with a strong imagination and an equally strong bank account could order themselves up a rocket powered go kart. Or if you preferred, an 850HP turbo-diff to bolt onto your car.
When I was a kid, I lived close to a lake and would have sold a million seed packets to get a twin-turbonique mini-hydroplane!
Link to Iowahawk Tubonique post
Link to Turbonique Gallery on The Rocketman.
Link to Onemansrace's Flickr stream.