They had one of these on display at Epcot's Innoventions pavillion not long ago. The demo was amazing...after sending it up stairs and ramps, the sales dude sat a volunteer in the chair, made it elevate up onto two wheels, and gave the thing a SHOVE. The crowd gasped, expecting the woman in the chair to go flying off the stage, but the chair just sort of skipped forward a little and shrugged it off, wiggling on its wheels, looking for all the world like a large man who'd just been bumped into. It was stunning.

Apparently you can lead the Segway (his $5K self-balancing scooter) up and down stairs by hand. You don't ride on it, it's wheels aren't right for climbing, but you can sort of drag it in a self-powered mode and it can handle the stairs. That's good because it weighs 80 pounds so you wouldn't want to carry it.