According to Bradley, the Quest event next week should supposedly be much better than last year's and include some (game) surprises. We all know they're working on GTA, Splinter Cell, and Asscreed. There's also whatever the Asgard's Wrath and Lone Echo devs are working on. There's also Walking Dead S&S Chapter 2, the Boneworks related game... What else could there be? 

Someone did ask about Halo and Bradley said no.