At the Pi Party, the lovely people from Pi Borg turned up with an ickle, tiny, tiny robot called BoB, aka The Bot of Bits. Made from a Raspberry Pi Zero and a Zumo Chassis, together with their new Thunderborg motor controller, BoB is a zippy little thing that turns over if you stop him quickly! You can read how to make your own on Hackster.IO.
You can see a video of BoB in action below: