Google has developed Cardboard with its own Android operating system in mind and you'll find over 30 compatible apps in the Play Store to mess around with.
I decided to use my iPhone 5S and try out the app VRSE, a photo-realistic, CGI film that immerses you in a short series of weird virtual reality experiences.
It worked well enough, though the field of view isn't as wide as a larger handset's would be - which even then is cutting it close.
The iPhone 5S's 4-inches, or 5.7-square inches, isn't as immersive as the Oculus Rift, of course, but even the Gear VR does a better job - which is to be expected.
Still, there are plenty of apps that work decently enough with Cardboard. Most are games that use Android devices, but more are being released for both Android and iOS.
There are also VRSE-esque experiences like Google Earth or Photo Sphere, in which you are simply plopped into scenery much like a virtual tour guide.
Google Cardboard is wonderfully cheap and fun to play with, if you want to dip your feet into virtual reality but don't want to spend $199 (about £126, AU$228) for a Samsung Gear VR. You'll barely make a dent in your wallet if you're simply curious about the weird contraption. There's also a decent amount of apps for you to use it with.
Since Cardboard costs so little, there's little to dislike aside from the obvious. Regardless of how accessible, Cardboard is still not the immersive virtual reality experience you're looking for.
Google's ingenious, little do-it-yourself project works better than I expected, considering it's just a piece of cardboard with two lenses attached, and then some.
This may be basic virtual reality "tech," but there's definitely a certain appeal. The novelty of building your own VR device is a brilliant move. Coupled with cheap parts and untethered mobility, Cardboard is a great introduction for those skeptical about VR.
That said, do not expect the mind blowing experience of Oculus Rift, HTC Vive or Project Morpheus. Then again, it's not as if Cardboard is trying to be any of those. Rather, Google has cooked up an accessible piece of virtual reality that nearly everyone can enjoy. If you're on the fence about this whole "VR thing," then you have little excuse not to dive in.