It may sound far-fetched, but:

It'd be astonishing to see a new gaming mechanic similar to the Oculus Rift, except that it would use your surroundings as part of the game.
Basically, it would be a headset that would be transparent and would project a HUD, enemies, objectives, etc onto your headset screen. You would have a controller for whatever kind of game it is; rifle, golf club, motion trackers (some kind of gloves?), etc.
For now, let's say it's an FPS. It'll take the surroundings around you and project the enemies and basically allow both the player and the AI to use those surroundings as cover, movement, etc. It would bring an unspeakable amount of interest in traveling for an exhilarating experience in different locations, multi-player maybe being a possibility where Wi-Fi is available?