Google Cardboard

Forbes breaks it down:

Google’s answer to VR? Cardboard. Or, rather, a DIY cardboard headset equipped with cheap lenses into which you slide your smartphone. Simply download the Cardboard app and you’re ready to roll, all for a few bucks in materials. Which is—let’s face it—about as weird an idea as anyone could dream up, but also sort of brilliant; a truly “open” solution to virtual reality that hearkens back to Google’s roots and commitment to open development. And one that sidesteps a lot of the challenges facing other VR gadgets by utilizing the ubiquitous smartphone. The actual construction of the cardboard VR headset will probably deter many would-be virtual-reality-goers, but it really doesn’t look difficult at all for anyone with a knack for putting stuff together. Almost certainly kits and fully-assembled versions of this will be available for sale within…days? Hours? Soon, in any case. I suspect we’ll even see more expensive, less “disposable” iterations pop up. After all, this is sort of the point: What Google is doing with Cardboard is opening up the possibilities of VR to basically anyone.

Here's the website.