Valve loves to experiment with their Steam client and you can now put a checkbox next to VR. They've announced a new feature in the beta where you can turn on SteamVR, which is Big Picture mode with the Oculus Rift. Instructions are in the announcement, but you might also need to do this:
Having experienced the updated Oculus Rift at CES last week, I'm kind of excited to see how this works. Valve's currently holding their dev days conference where more news like this could pop out with little fanfare.