I have to admit it, but iRobot’s Roomba is just the coolest thing to watch. I love how it circles around the same location over and over, how it plays a tune “Charge!” as it heads for its charging unit, and how clean it gets the areas it tackles. Fun for me — and my geek husband — who figured out where to place the sensors so it wouldn’t crash into my grand piano. And particularly appealing to have it run around under our bed, where we never push a vacuum cleaner. And from reading the reviews, it is endlessly interesting to cats and dogs.