As promised, Valve launched an experimental SteamVR mode this week, allowing users to test out virtual reality headsets like the Oculus Rift with the Steam UI. The launch comes just a day ahead of Valve's Steam Dev Days conference in Seattle, where talks feature discussion on VR hardware development, and how to integrate VR with various Steam features.
In one talk, Valve is showcasing a prototype that reveals "what VR is capable of within a couple of years," and the studio looks likely to be working on its own VR headset, though no official announcement has been made. Valve's Brian Coomer recently said "there's also technology in development at Valve based around head-tracking and headset manufacture and design," and that the studio is working with other companies on VR tech, too.
To test out SteamVR for yourself, follow the instructions here.