I've always wanted to try my hand at surgery on a genuine medical grade surgery app. Sure, I don't have any training, but how bad can you really mess up on these things? And I hear the medical establishment is very interested in VR.
Historical re-enactments are another big one for me. I'd love to see what it was like as the Russians stormed into Berlin, not as a german sniper but just to watch the non-gamey version of events.