Last weekend visiting my brother in Calif, we got to ride a Segway briefly at the San Jose Tech Museum of innovation. The movies are 1.5 MB, and you'll need Quicktime 6.
http://www.netjeff.com/video/jeff-segwa
http://www.netjeff.com/video/joe-se
At first it felt a little unstable. By the end of the minute we each had, it was easier, but you still had to think a bit. I'll bet that after 15 minutes of usage, you wouldn't even have to think about it. Way easier than learning to ride a bicycle.