Epic Games is currently holding a Twitch stream on which they've just revealed an upcoming title - a new Free Unreal Tournament game for Windows, Linux and Mac. Follow the link below to see the stream yourselves!
EDIT: Oculus Rift support for UE4 has been confirmed, the team is also working on implementing skeletal animation on the basis of motion controllers. The engine will be made available for developers on iOS, Android and HTML5.
EDIT 2: The stream has finished, visit the official blog below for more information.
Twitch Stream
Official Blog Post