Bungie's original Halo title, first shown to the public running on a Mac at MacWorld in New York in 1999, subsequently re-targeted for the Xbox and released in 2001, then ported to the PC by Gearbox and then re-ported to the Macintosh again by Westlake Interactive and published by MacSoft Games, has now come full circle: the Macintosh Demo of Halo is now available. You can download it from these locations:
Thanks to Louis Wu at HBO for the heads-up.