Lots of tinkering around with VR, but it seems open-source games are still not picking it up that much.
I guess the main reason being that none of the mainstream platforms play along well with Linux yet. But at least for the Valve SteamVR stuff it seems to be around the corner, OSVR (
http://www.osvr.org/ ) seems to partially work, but their consumer grade hardware is still a few weeks away, well and there is Google Cardboard, which is shaping up to be a quite capable framework for VR on Android (but of course is a bit limited by the hardware and the lack of standardization in that regard).
After a lot of hype and prototype projects, such as Occulus support in Torque3d, Tesseract (got removed again), the most mature open source support for the main VR platforms seems to be implemented in the jMonkey3D Engine... but it is not yet mainlined and still has ways to go.
Cool is also the Quake engine port (actually Darkplaces, that also runs Xonotic etc.) for Google Cardboard and Gear VR:
http://www.quakevr.com (I took the liberty to extract the GPL sourcecode here:
https://github.com/poVoq/Quake-1-Cardboard-Port-QVR ). It also runs mods, but most are not working out of the box and Xonotic requires probably a bit too much performance for todays smartphones to run well as VR.
In general this is something that probably holds things back, i.e. not that many people have hardware capable of running VR games well, and dedicated headsets are also still very expensive. Cardboard is the cheapest option, with mobile phones of the current mid-priced (~300$ + >50$ for a good headset) generation running some games quite ok. If you are shopping for one, make sure it has a gyro and a 1080p screen around 5" big. Samsung's GearVR is probably the highest quality cheap option right now, but their system is closed down and Samsung phones are also not very open to custom roms etc. I have a Asus Zenfone2 which works quite well with Cardboard, but the PowerVR GPU and the x86 cpu (not the best Android support) make it somewhat difficult to recommend right now. The Nexus5 is probably a safe bet, and even my old Nexus4 works well, but the resolution (720p) is a bit low (and it also has a lot of overheating problems in general).
For headsets, I would recommend to first get a real Cardboard (i.e. the cheap ones made from cardboard) to try it out. They work surprisingly well and in fact offer a better immersion than many of the cheap plastic headsets currently being flooded on the market. For an upgrade, there are some better ones (I hear BoboVR Z4 is good, but I have not tried) that are a bit more expensive, but offer better Field of View and sharper lenses.
I was a bit stupid and got a cheap one after using the real cardboard one for a few weeks... logic being, if the cardboard one is good, how can a improved one be worse? But evidently Chinese companies never try their own products and managed to make it much worse than something made out of cardboard for 5$
But the head straps etc. were ok, so I modded the hell out of it and now it works quite well.
If you can wait, get the second generation that will come with a dedicated gyro like the GearVR though. It is supposed to offer much faster head-tracking and Google is working on supporting that with Android N it seems. So sometimes later this year I guess.
Highly recommended is also to get a good swivel chair and a Bluetooth gamepad to avoid cables getting into the way. Some smartphones also work with a USB OTG adapter and a Xbox360 or similar gamepad, but that is a bit hit and miss and works only on rooted phones in some cases. I also tried with a bluetooth mouse and keyboard (I had those for Ubuntu Touch convergence tests), but you really need 360° movement for many games, so that became a bit inconvenient.
Generally a good resource for CardboardVR related news is the reddit group:
https://www.reddit.com/r/GoogleCardboard/ I also follow the OSVR reddit group:
https://www.reddit.com/r/OSVR/ as this seems to become the most Linux friendly and hackable option (at a somewhat affordable price) in the near future.
Interesting is also a recent prototype (VRidge) that uses game streaming to emulate a Occulus VR headset with Google Cardboard. Not open-source and currently only works with a WindowsPC to run the software, but it shows lots of promise and the technology is actually quite simple it seems: Stream a stereoscopic 180° video in >1080p to your mobile, and do the head-tracking in the phone on that video directly to avoid latency issues. If you connect the controller to the PC directly and maybe also add a positional head tracking camera, this will likely give you quite high quality VR using cheap equipment and standard software soonish.
Generally though there is still a bit of a lack of real games, most of it is just nice demos and early prototypes. Some show really a lot of promise though and there are also some cool stereoscopic VR videos of various topics available for download / Youtube (big files though, as high quality 4k is best for that).
Anyways... I just wanted to note down some thoughts and what I tried recently. Maybe it motivates someone to also start fiddling with VR. It's still early days, but it is already quite amazing.