It sounds made up: Your smartphone, a couple plastic lenses, and some strategically cut cardboard come together to form a virtual-reality headset.
Yet that's the, er, reality of Google Cardboard, the weirdest, buzziest thing to come out of Google I/O earlier this month.
If you've been itching to try it, you have two options: Build one yourself, or order a kit to the tune of around $30 (converted, about £18 or AU$32), or less if you can find a deal. Either way, here's what you should know about using it.
Make sure you check the list of supported Android devices before you spend any money on materials. I tested it with a Motorola Moto X, OnePlus One, and Samsung Galaxy S4, and all worked just fine -- though the 5.5-inch One was a little big for my pre-assembled kit. The resulting "squeeze" produced constant pressure on the volume buttons.
If you're building your own, obviously you can tweak the dimensions to better accommodate larger devices. And for those who find Google's design files a little intimidating, there's a very helpful video showing how to build a Google Cardboard from scratch.
Where to find VR content
Once you've got the hardware, you need content to view. Unfortunately, as of this writing, there's only one app that can take advantage of Cardboard, and that's Google Cardboard. But it certainly shows off what the technology can do. Its seven demos are as follows:
Earth: Borrowing from Google Earth, this demo lets you fly around a city or mountainside, looking up to soar up, down to soar down, and in any direction to "steer." Pressing the magnetic button stops and starts your movement. And it can also fly you all the way to space, which is where you'll choose another destination (again with a button-press).
Exhibit: Check out a 3D-modeled art "exhibit" of various historic masks. Click the button, ViewMaster-style, to move from one image to the next.
Photo Sphere: Quick! Have you snapped any photos using Android's panorama feature? Here's your chance to get a real 360-degree view of them.
Street Vue: Take to the streets of Paris in an alarmingly fast (and rather choppy) "ride," but you can stop anywhere along the way for a virtual reality view of the surroundings.
Tour Guide: While you're visiting Paris, here's your chance to explore the Palace of Versailles. There's no movement, though, only immersive panoramas of various rooms and the grounds outside. Very cool -- but not quite a substitute for actually going there.
Windy Day: Already familiar to Moto X owners, this adorable bit of VR storytelling feels like something from the Pixar archives (and in fact was created by a Pixar director). It's worth popping on headphones for this one.
YouTube: Choose a video from a 3D wall of popular picks, then watch it on a screen that fills your field of vision. Really cool.
Although that's all the app has to offer, there's a bit more to see: Fire up your phone's Chrome browser and head to g.co/chromevr, which is home to eight experimental games and activities. Instead of using the magnetic button to select one, you simply point your head (and the accompanying heads-up "cursor") at it for a few seconds until it triggers.
"Experimental" is definitely the key word, though. On the Galaxy S4, Chrome froze up almost immediately after the selection page loaded. And on the Moto X, there seemed to be some gyroscope "drift."
Even so, once you get on that virtual helicopter or rollercoaster, it's hard to get off. Cardboard is certainly an interesting proof of concept, that concept being that decent VR doesn't necessarily require a $2,000 headset.