Windoro: The Roomba for Windows
New Roomba-like household robots are popping every day, now. The Windoro consists of two scrubbing modules, one on each side of the glass, held together with magnets:
The robot uses distance sensors, attitude adjustment, and obstacle detection while doing its little window waltz, employing detergent and a series of spinning pads to wash up as it goes.
This robot was developed by the Pohang Institute of Intelligent Robotics in South Korea. You can watch a video of the robot in action at the link.