What was the first coin-operated video game?

According to ComputerHistory.org, the first coin-operated commercially available video game was called "Computer Space." It was developed by Nolan Bushnell in 1971 with help from Ted Dabney.

The game was a very basic space shooter in which the player controlled a spacecraft fighting against two flying saucers. The game featured four buttons: two for firing and two for moving. As noted by Technologizer.com, the game helped ignite the video game revolution, though it sold poorly. Nolan Bushnell went on to become one of the founders of Atari, and he is considered a key figure in the history of video games.