It's an entirely modular phone – in other words, you build it yourself. But you won't need a degree in computer science to do so. Instead, you just put together the modules, get to grips with the software and attach the customisable phone enclosures. Couldn't be simpler.
Because it's open source, you can hack it to your heart's content.
It has all the usual skills you'd expect from a phone, including GSM, GPRS and Bluetooth. Plus it uses the world's smallest system-on-chip which is usually used for wearable and devices connected to the internet of things.
As you can see from the picture, it's also mighty small.
Add-ons include a 1.54-inch touchscreen, LEDs, a 520mAh battery and an NFC chip for wireless pairing with speakers and other accessories.
Read more: What is Project Ara?
Its kraft paper enclosure is cheap, strong and easy to draw on, so you can make your phone look however you want. Plus it's very clever. You can connect it to your smart thermostat and have it text you if the temperature in the home exceeds a certain level. Or have it call you if your bike is stolen. The possibilities are endless.
It's stormed past its funding goal and will ship in December. It's extremely cheap too – just $12 (£8) gets you the core module.