The Inquirer is reporting that the SDK for Microsoft's next generation Xbox is being released to developers. And it's running on a Mac.

Several years after being purchased by Microsoft and becoming a studio that developed games for MS' largely PC and Windows-based technology underpinning the Xbox, could Bungie be coming full circle, soon to be working primarily on Macs while they develop games for the PowerPC-based Xbox 2?

Only the Shadow knows.