The guys who own and built the Schlitterbahn water parks are the brains behind many slides in use at various water parks to this day. I believe even certain ones at Kings Island (I'm fairly certain my fave, the giant funnel looking one, is one of their creations), are their creations.
There was a reality show following them as they were attempting to build the tallest raft drop. The show ended before they ever got it to work. Allegedly they ended up opening it without ever perfecting its problems and the then Kansas State Representative, Scott Schwab's, 16 year old son got decapitated on the ride.