Marathon was also the title of a video game series released for the Macintosh. There were three titles in the series: Marathon, Marathon 2: Durandal, and Marathon Infinity. Marathon 2 was released on the windows platform as well.

The story centered around a "rampant" AI named Durandal that took control of a colony ship called the Marathon. Durandal goes onto throughout the series to attempt to move beyond the constraints of physical space by using the technology of a dying race called S'pht (or compilers as the humans called them). The player was basically at the whim of Durandal most of the time, thereby creating some weird situations for the player.

The original pretty much revolutionized first-person shooters for the macintosh because:

1) it was the first one to hit the OS
2) it actually was fun and engaging with a amazingly complex storyline that went beyond 'kill it because it's there'
3) It had excellent network capibilities at the time.

The games were created by Bungie Software who also created such games as Myth, Myth II, Oni, and Halo.