This is OSCAR, the Overly Simplified Collaboratively Actuated Robot. He's built from an old Roomba and an Android tablet, and he's about to make Google+ a lot more interesting.
The robot is controllable by users in a Google+ Hangout, allowing the audience to interactively explore OSCAR's environment via his on-board camera.
Through a web server on the tablet, and a custom Google+ Hangout, users in the group can enter commands into a queue, giving everyone a turn to control the curious robot.
Visit the creator's website to learn more, or pick up his code to give it a try yourself! Hopefully this is the start of a lot more clever uses for Google's social networking infrastructure.