What will Microsoft bring to E3 this year?

There's been a lot of news recently surrounding Sony's new IPs, big game sequels, and impressive Vita releases. Nintendo has a whole new console to usher in which will always bring in lots of hype and new game announcements. Even companies like Valve and Apple could be making big splashes this year with surprise announcements. Yet on the horizon of all this, what will Microsoft and Xbox be revealing this year?