If you're considering building a new VR game or app experience, you may be facing new challenges in how to create realistic scenes, how to move your characters across space without dizzying the player, and how to choose between click and gesture controls depending on what's best for your setting.
Daydream Elements is a new open-source app by Google that provides tech demos for many scenarios regarding these 3 areas: locomotion, menus and virtual controls, and rendering and lighting. There's also a full documentation page with explanations and details on each aspect, plus the source code on GitHub, so you should have everything at your disposal.
You'll obviously need a Daydream-compatible device and a headset to view the different demos, and you should at least be interested in VR in some way to enjoy the intricacies of developing for this new era of experiences. Also, teleportation is real, folks!