Created by William Higinbotham in 1958, Tennis for Two basically “simulated a game of tennis or ping pong. It was based on analog, rather than digital computing.” Video after the jump.
Unlike PONG and similar early games, Tennis for Two shows a simplified tennis court from the side instead of a top-down perspective. The ball is affected by gravity and must be played over the net. The game was controlled by an analog computer and “consisted mostly of resistors, capacitors and relays, but where fast switching was needed – when the ball was in play – transistor switches were used”.