The Omni is an impressive Kickstarter project by Virtuix that will allow you to transfer physical movement into a game.
Basically, you will be able to work up a nice sweat while playing you favorite game in a way that will leave Wii Fitness to shame.
In fact, Virtuix says that the Occulus Rift is meant to be used with this new system. You cannot get a full immersive experiences with the Occulus without having a natural tether.
They make a great point. If one were to wear the Rift, they would be unable to move safely. Sure you can sit on the couch with your fancy portable headgear, but that almost defeats the purpose of even having it.