Xbox LIVE Games
One of the built-in apps, Xbox LIVE Games, acts as a central place for gaming activity. Games can plug into it and work over the Xbox LIVE system, including earning points.
It also means that games could allow multiplayer action between people using different devices entirely. Xbox LIVE Games has been neat on Windows Phone 7 and is a great piece in Windows 8, even if you do not own an Xbox.
Justin James is the Lead Architect for Conigent.