Joke

Back in the days of the Roman Empire, the famous Emperor Nero instituted a new game. The players would take those little disks you set your glass on in order to protect the furniture, and see who could get the most distance rolling them across the floor.

They were the first roller coasters. Back in those days, the disks were made of iron, and they would bet on whose disk would roll the farthest.

They called them ferrous wheels.