Unity

Unity is a tool for making games and VR experiences of your own.

You'll need the Unity beta. Then, to make your project VR-enabled:

1. Go to the Edit menu and select Project Settings, then Player
2. In the inspector panel it opens up, expand the XR Settings section and hit the Virtual Reality Supported checkbox

You should then see your project in the headset next time you hit the play button (assuming your headset is hooked up properly and SteamVR is running).