Right now, the term "virtual reality" still means "headset" for most people. What we should really think when we read "virtual reality" is first-person immersion. The headset -- like Oculus VR's Rift, Sony's Project Morpheus, and Samsung's Gear VR -- is simply the first tool for creating that sense of immersion or "presence." But once you're in a headset, the first things you do are the undoable: reach out with your physical hands into virtual reality. It's not exactly surprising, then, that Oculus VR would acquire Nimble VR -- the company behind Nimble Sense, a camera and software combo that brings the world around you into virtual reality. Think of it likeKinect: cameras that are able to track your skeletal movement and create a point cloud around you, which then translate that data into a virtual representation on-the-fly.
Still confused? We've got a video hands-on of Nimble VR's Sense camera from early November below the break, used in-tandem with Oculus VR's second Rift development kit (pictured above).

http://www.engadget.com/2014/12/11/oculus-nimble-vr/