riding a bike is a cool thing to do, although I think it limits the imagination. Human powered vehicles are a great way to stay in shape, although in order to roller skate you have to use your imagination constantly. There are often moments when you have to think your way out of falling down, or not getting hit by a car … which sucks. Being great athletically then becomes an art form, operating a bike is not very artistic. i.e. there is artistic roller skating but there is no artistic bike riding.