Ubuntu Xenial isn’t an officially supported operating system for the Raspberry Pi, but there are images available for both the Pi 2 and Pi 3 in Trusty and Xenial versions. I’ve found the Xenial image works quite well, but as I recently discovered the Bluetooth chip that is present on the Pi 3 isn’t detected at all out of the box. Getting it working turned out to be a bit of a mission.
By this point I really don’t need to explain how great the Raspberry Pi is - a nice useful lump of computing power for not very much money1 . The low price point does mean that you loose some features that come standard on larger computers though, and one of the less obvious omissions is a ‘real time clock’ module to keep track of time while the main computer is powered off.