The fabulous Roomba

Meet Roomba, the robot vaccuum cleaner from iRobot.
Tim and Linda have three of them - one for each level of their home.
We got a demonstration yesterday when they launched the one on the main level. It goes back and forth in a seemingly random pattern, buzzing across the carpet until it hits an object - wall, furniture, foot, whatever - then veers off in another direction until eventually it has covered the entire room. It apparently builds an internal map of the space being cleaned and when it's done, it crawls back to its charging station to await a new mission.
It tends to get hung up in a tight space now and then and needs to be rescued.
We were particularly amused when it appeared to be humping the fluted pedestal of a table near the TV and had to be redirected.