Jason Rubin (director of Crash Bandicoot, Jak & Daxter) and president of Oculus Worldwide Studios teased the exclusive on Twitter:

Looking forward to another big @Oculus Studios exclusive partnership and game announcement tomorrow!

— Jason Rubin (@Jason_Rubin) December 15, 2015

Is there a game that comes to mind that could be a fitting exclusive for Oculus that would make VR relevant to you, if it already isn't?

UPDATE:

Game is The Climb from Crytec:

Launch title for Oculus:

"It's a game about scaling up a mountain from a first-person point of view. The gameplay is deceptively simple: holding down the left or right triggers causes your in-game avatar to grab any viewable, in-distance ledge with their left or right hand. You "aim" at new ledges simply by looking, craning your neck, shifting your body weight when necessary. If the nearest ledge is too far to reach, you can attempt to jump for it, but you'll need to look well above where the ledge is actually located.

Crytek has The Climb running at a continuous 90 frames per second and a resolution of 2160 by 1200. These are far more taxing demands than the average triple-A game of 2016, and yet it also still manages to look gorgeous."

http://www.polygon.com/features/2015/12/15/10181740/the-climb-crytek-oculus-rift-virtual-reality

Teaser trailer:

https://www.youtube.com/watch?v=6hqUx2SOTAQ

Titanfall 2.

Half life 3 oculus exclusive

Respawn must hate their game a lot then. But then they opted out of releasing on PS4.

Is this the part where we open a new Pandoras box and by that I mean a pointless war for nothing?.

All we're getting from this is a partnership, one which we tend to see a lot of not only in this industry but many others as well. What I'm not seeing is a list/ different platform VR wars and even if we do they are going to be made by those that love seeing wars (Because I can't say PC vs console without someone thinking a PC user is the one sparking trivial crap off).

Don't be ridiculous!

Half Life 3 will be Valve's & HTC Vive exclusive .

OT: Given that Carmack is involved in Oculus, I'm going to say the new Doom (but only for VR devices, ofc).

Doom is ID property. Which is Bethesda owned. Bethesda is suing Oculus due to things Carmack supposedly developed while being in ID. Carmack has zero control over Doom or any ID IPs.

This will definetly not come. He (Carmack is not even present on their (IDs) events anymore. Doubt there is any good will between Carmack and ID left.

With ps4's vr, I don't see that many full blown aaa long story adventure, fps games. But I see more user generated content, f2p arena fps, platformers, with potential of user creaated stories etc...

On the pc I see full blown high graphics adventures and universal vr for most games and mods for existing ones.

One more mainstream: Wii/now psvr

and One for more core players(Resistance, Killzone, heavy rain): Move/now occulus

Wii sold exceptionally, Move sold to the core fans.

PSVR will sell lots more,
occulus will have less a fanbase but a much stronger dev base

OP updated.

I know Doom is owned by id Software, which is owned by Bethesda. Still, Carmack was the man behind those games. that's why I mentioned it.

But I didn't remember the bad relations between Bethesda and Oculus, that surely makes that partnership a lot harder.