Valve has "figured out what affordable Virtual Reality (VR) hardware will be capable of within a couple of years." And they will show what their vision of the future is at an upcoming developer-only event.
Discovered by IGN, Steam Developer Days will host a talk called "What VR Could, Should, and Almost Certainly Will Be within Two Years." According to Valve, the company has "assembled a prototype which demonstrates that such VR hardware is capable of stunning experiences. This type of hardware is almost certainly going to appear in short order, and the time to [start] developing for it is now."