If you've ever ice skated at an indoor rink, you've probably seen a Zamboni. It's the machine that's used to periodically smooth out the surface of the ice so it's easier to skate on.
Some Zambonis are hand-pushed devices, while others are vehicles with a driver. During professional ice hockey games, a Zamboni is used to clean and polish the ice between periods. Busy indoor rinks smooth out their ice in the same way. This ingenious machine, which shaves, washes, wets, and smooths the ice, was invented by an American engineer named Frank Zamboni in the 1940s.