Maze War (also known as The Maze Game, Maze Wars or simply Maze), developed in 1973-74, was the first networked, 3D multi-user first person shooter game.
"Maze first brought us the concept of online players as eyeball "avatars" chasing each other around in a maze). From its humble 1973-1974 origins on the Imlacs PDS-1 at the NASA Ames Research Center in California, to its life in project MAC at MIT, on Xerox Altos and "D* Machines" running on early ethernet, to versions ported to Mac, NeXT and PalmOS, Maze started it all. Today's massively multiuser 3D games owe a great debt to Maze and those who created and kept on porting it to new systems for the past 30 years. Maze is the reason why nobody can claim ownership of the rights to the invention of a multi-user 3D Cyberspace and is another of the major gifts to innovation made by early net pioneers" (Digibarn Computer Museum, accessed 04-15-2009)