One week ago Bungie filed a new trademark application for Marathon, the FPS superstar of Mac gaming's brief apogee during the mid- to late-1990s. There are few details beyond that but the paperwork's enough to stoke fantasies of a reboot.
It's definitely Bungie filing it, though the application notes the first use in commerce was Jan. 1, 1995, so this could just be some housekeeping required to keep that mark fresh for the studio. Marathon, in addition to having bitchin' box art also during that period's heydey, released for the Mac in late Dec. 1994, and spawned a sequel in November 1995.
Also keep in mind that Bungie seemed to have something Marathon related at X10.