wiki) as I have tried this great invention last weekend in Paris.
There is company in Paris which offers several tours, one of those is with a Segway. The tour is around four hours and you get to see the more relevant parts of the city (Eiffel tower, Les invalides, Louvre on so on).
Obviously, the city itself is worth the visit but the Segway is just amazing :D
The machine is really easy to drive. After a short explanation and a few minutes of practice, you can start "riding" the city :D
To speed up you just need to bend forwards, to break or go backwards just bend that way and to turn around just move or best say, push the handle to the right or to the left. This will make that one wheel will move slower than the other an the machine will turn around that wheel.
Only drawback is that every one is looking (or even making pictures) in your direction as you pass by ;D