Ok, I really don't want to get into the habit of plugging products, but once in a while, something strikes me as so ingenious, and so unique, that it really deserves to be brought to people's attention. Besides, I can't think of anything else to write about.
A good example of this is the Trikke (www.trikke.com), a human-powered 3-wheeled scooter-like vehicle. The Trikke has a tall steering column with handlebars and brakes, and two back legs that you stand on. For the first couple of weeks of diligent practicing, it seemed to me that this would only be good for rolling downhill and crashing into things.
Once I finally got it, though, I was amazed. You can actually make this thing move at a pretty good clip just by turning the handlebars and leaning from side to side. You do have to get the hang of when to do what, but once you do, it's very natural. Moreover, as you play with it, you find all kinds of subtle ways to vary your weight to change the movement. After a short while, it becomes like dancing ... shifting your weight, swiveling your hips, and establishing your rhythm. You can actually propel yourself by dancing. I've done trips of about 15 miles, but I know others who've gone up to 100 miles in one (all day) outing.
There are two downsides to this thing. First, going uphill is a bitch. You can do it, but it's slow and difficult.
Secondly, oncoming bicyclists, walkers, roller skaters, etc. will think you're out of control, because you're weaving from side to side. They may jump out of the way, shout nasty things, or threaten you with bodily harm. Fortunately, these are outnumbered by the people who will say "Cool!", "Did you invent that?" and "Where did you get it?"
The upside? It's really fun!