Plot: Tennis for Two is a sports video game that simulates a game of tennis, and was one of the first games developed in the early history of video games. Wikipedia
Plot: Maze, later expanded and renamed to Maze War, is a 3D networked first-person shooter originally developed by Steve Colley, Greg Thompson, and Howard Palmer for the Imlac PDS-1 computer. Wikipedia
Plot: Spacewar! is a space combat video game developed in 1962 by Steve Russell in collaboration with Martin Graetz, Wayne Wiitanen, Bob Saunders, Steve Piner, and others. It was written for the newly installed DEC PDP-1 minicomputer at the Massachusetts Institute of Technology. Wikipedia
Plot: Pong is a table tennis themed arcade video game, featuring simple two-dimensional graphics, manufactured by Atari and originally released in 1972. Wikipedia