Cardboard is a software developed by the team at Google, that gives you the opportunity to enjoy your favorite VR experiences straight on your Android smartphone or tablet. The cool thing about this application are the included demos, such as Tour Guide where you can visit Versailles and get guidance from a local guide, Earth in which you can simply hover over our world as you discover amazing landscapes, Exhibit that gives you the ability to explore cultural artifacts from multiple angles, My Videos where you can simply enjoy your videos on a large screen, and more.
The user interface of this app is very straightforward and it contains two separate sections. The first one contains your library of content and the second one gives you the ability to download some apps for VR. Don't expect this piece of software to rock your world with an amazing virtual reality experience, but it is a decent tool to get a bit familiar with this innovative technology.
Keep in mind to not use this app while performing other tasks that require full atention, like running, driving, working, and more.