Not (directly) Applicable
The Roomba as a household robot (of the future) is automated, and doesn't need to interface with a computer. With that out of the way, iRobot's Roomba as a hardware platform is great!
Theres the Roomba laser sight bb-gun which'll track an object pointed with a laser sight. Theres the Poster printing roomba.
Theres a serial port on them, and the interface is documented
Add a laptop running linux to the top to interface to this port, and its running with linux!
Oh yeah, and it vacuums.
