Xbox Smart Glass
Microsoft wants your phone and tablet to be able to allow Xbox Live content and allow these devices to control and transfer content seemlessly between devices. Xbox Smart Glass is going further by allowing multi screen support for both video and gaming applications. Features such as using the tablet to control play selection on madden, but then allowing you to adjust and control in real time. Look for big things to come, including waypoint compatiblity with the new Halo 4!
Source: Microsoft E3 press conference