This is the world's first frozen margarita machine, invented and built by Mariano Martinez in 1971 from parts of a soft-serve ice cream maker. His inspiration: A 7-11 Slurpee.
Today, it resides in the collection of the National Museum of American History, where a museum director once called it a, "classic example of the American entrepreneurial spirit."
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.