Google Cardboard is a low cost virtual reality headset that uses mobile smartphones to display the video. Cardboard plans are open source so that anyone can produce a cardboard unit.
Google Cardboard can be built with cardboard, magnets and lens to focus the picture.
Assembly of the unit is easy for anyone to do.
Google has created a Cardboard app for Android and iOS to demonstrate the capabilities of cardboard. It is available in the App Store and Google Play.
Additionally, there are a number of apps that support cardboard via side-by-side (SBS) 3d rendering or SBS video.