I think they're kind of interesting, but . . . as a nation, we're overweight from not getting enough exercise already. Do we really want to encourage our kids to cut out the only exercise they DO get by letting them roll around instead of walk?
My response to this, they are not a lazy activity. They make walking fun and it get's kids out of the house to use them. I may not have liked him gettingthem for Xmas, but then, they're better than an XBox 360 right? They're similar to roller skates in that, if you want them to work, you have to move your body. There is also balance and coordination taken into consideration with these as well, so they are a good mobility toy.
My son's school has also banned the wheels, but not the shoes themselves.
As for the adults that want them, I know Footlocker at my mall carries them in adult sizes, and if you shop online, I'm sure you can find them, I know they are made. Lots of high schoolers like them so there is a market for adult sizes, and the company made them... I'm just not sure how available they are in stores.
I did a quick Google for them *Heely's Adult* and found this link:http://shopping.yahoo.com/s:Skates:4168-Brand=Heelys
They're not cheap, but from what I can tell they're of a decent make and they look alot like my Vans' as far as comfort goes (and I paid $120 for those!), and my Vans are the most comfortable sneakers I've ever worn!