The Segway may the flashy, trashy, geek-tastic, commercial flop that everybody knows Dean Kamen for, but the man is the greatest inventor of our time (in my opinion). He is the Edison of this age.
The Segway saw much more limited use than Kamen expected, but it is a great device in some applications. My kids went to a college prep school in an urban area and the security people had one. They could cover the area very quickly. Been using it for years.