I got to play with the HTC Vive yesterday for the first time. The difference between sitting down with a VR headset and moving around with it on combined with motion tracking is astounding. This particular demo gave me an incredible sense of actually being there in the virtual world.
The last time I got to play with VR was early this month, when Juegos Rancheros had Superhypercube on display for people. THAT was a lot of fun too. Unfortunately there don't seem to be any videos up yet that do justice to that experience.