I recently read about a Lithuanian art student in London who had grown up at an amusement park in the old Soviet Union. As a PHD project he had devised what he called the Euthanasia Coaster. Its purpose is to kill its rider. I've enclosed the artist's conception of the coaster's single seat.
If you've ever ridden a roller coaster, you know there is always a long, clanky climb to the top, and then gravity takes over. This guy's design uses gravity to make more gravity. The initial climb is to a height of more than 1600 feet, followed by a plunge that accelerates you to more than 200MPH. Then you go into a series of loops, seven in all, each one progressively tighter, that spin you around like a centrifuge, subjecting you to ten times the force of gravity for a full minute. He assures us the blood draining from the head, starving the brain, will be enough to kill you.