Recently had the chance to try out the Vive at a friends house. Played a base defense game where I was shooting arrows at dudes trying to storm the castle, another one where I walked around someone's laboratory, and at one point shrunk down tiny and was walking around the same laboratory? Was pretty intense.
Oddly enough, my favorite experience was walking around the solar system. Was messing with a couple planets, and I turned around to have the Sun, to scale, right in my face. Was amazing! The whole thing has me very curious about the educational application of VR. My 4 year old son would flip his lid if he could walk around in space and play with the planets like I did.