Gavin, Elaine, and Melissa got together last year and arranged for Segway Polo on my birthday. As my luck would have it, the day of the event was met with a torrential downpour. Since Segway's don't operate well in two inches of standing water and the resulting mud, we postponed the game. Not once in the subsequent year did we find an opportunity to reschedule the game, so they came up with the brilliant idea of taking the Segway tour of Disney's California Adventure while on a recent trip. What a blast.
Two Disney cast members teach you how to use a Segway and then take you on a tour of DCA before it opens. Why do it before the park opens? In their own words, "People do one of two things when they see somebody on a Segway: they either run away from it; or, they run towards it. Both are dangerous."
The Segway experience is like nothing else. Although completely impractical, you'll want to buy one after your first try. My recommendation is that you resist the urge. It's fine to be a nerd in the privacy of the Happiest Place on Earthsm (especially when no one else is around), but you might not want to be that nerd in public.