I'm sure I'm not the first person to think of this, but a few months back, I was watching a concert, and a thought came to me, "Why not have this in VR?" I was tempted to build the end product, which would essentially be a camera array that creates a seamless 360 degree, mostly spherical image. The idea is that the end result being transmitted to the Rift would actually just be a cut-out from the entire image. Then I also considered that the camera array would also need to have multiple microphones inserted at points. As a user turns their head, you'd need to mux the different microphone inputs at different levels to simulate what the user would be hearing. Some may suggest to just have the cameras/microphones turn, but the idea is to allow the same feed to support a lot of users.
I've been tempted to build a prototype of it a few times, but I've never been much of a hardware guy, so it'd probably be much more of a hodgepodge than the original Oculus Rift was.