Well that's not something I expected to wake up to.
I'll implore you to hop over to G4 to read Patrick Klepek's full breakdown of the situation, as he's been on the forefront of all of Activision's recent high drama since the day Jason West and Vince Zampella were terminated from Infinity Ward, but here's the gist of it: Bungie has signed a 10-year publishing deal with Activision, a deal that will allow Bungie to retain the intellectual property rights to whatever new universe it cooks up. The plan apparently includes bringing the new property to "multiple platforms and devices," which would mark Bungie's first foray outside the Xbox hardware in a good long while. Bungie claims that while it's been working on Halo Reach for Microsoft, it has another team led by Bungie co-founder Jason Jones that's already hard at work on this new property. If the delicious irony here isn't already apparent, this seems to be exactly the deal that West and Zampella were looking for with the Call of Duty series, though it took their termination from Infinity Ward, the formation of their new studio Respawn Entertainment, and the negotiation of a deal with Activision competitor Electronic Arts for them to get something resembling it.
There's more, including an open letter from Bungie itself, but I'm just going to let all this sink in for a little bit. Feel free to go absolutely bananas in the comments below.