Microsoft revealed their PAX East lineup and it's basically stuff you can just go purchase right now. The lineup includes Titanfall, Plants vs Zombies Garden Warfare, Forza Motorsport 5, Dead Rising 3, Ryse: Son of Rome, and Killer Instinct. It's worth noting that Project Spark will be there (which isn't out but it is in open beta), as well as Kinect Sports Rivals, which is a Kinect game so yeah.
What will be worth checking out is some of their ID@Xbox content ... comprised of just Super Time Force and Strike Suit Zero: Director's Cut. Really, just two? Well there's also some State of Decay DLC probably worth seeing?
Look, why in the hell are you going to go to a convention so you can wait in line to play games that were already released when there's so many unreleased games all around the place. Come on! Some of the panels and activities that Major Nelson detailed do look interesting, at least.