my brother and I had one called the "sumo". it was essentially an inflatable traffic cone. it had handles inside, at the tip of the "cone", and you basically layed down in there with your legs dangling out the back. The boat driver had complete control of the ride and my brother and I would do this thing where we would very slowly turn the boat at a sharp angle, so that the tube would be facing perpendicular to the bow/stern. Then we would slowly accelerate to tighten the rope, and just as it became taut, gun it. The slow initial movement of the boat would create a nice wake, which the tube would be shooting towards as the boat accelerated. By the time the tube hit the wake, we were probably going about 20-25mph, and if the conditions were right you would get a nice jump off of it. One time the conditions were a little too right and as I came off a huge jump, the tube dived straight back into the water tip first -- exactly where my face was. So of course the tube hits the water and stops abruptly but my face doesn't. Pretty sure I broke my nose and I still have the scar to this day. That was an enjoyable watersport, but the damn thing was always springing leaks (I wonder why...)