The beta for Half-Life 2 (including Lost Coast, Episode 1, Episode 2, and Half-Life: Source) has been updated with enhanced VR support. To opt-in to these changes open the Properties for Half-Life 2, click on the Betas tab and pick Beta from the dropdown (in a few cases this is labelled SteamPipe beta.)
The following Virtual Reality-related changes are included:
Improved readability of the UI in VR
Removed the IPD calibration tool. TF2 will now obey the Oculus configuration file. Use the Oculus calibration tool in your SDK or install and run "OpenVR" under Tools in Steam to calibrate your IPD.
Added dropdown to enable VR mode in the Video options. Removed the -vr command line option.
Added the ability to switch in and out of VR mode without quitting the game
By default VR mode will run full screen. To switch back to a borderless window set the vr_force_windowed convar.