I borrowed a bicycle yesterday and rode it around town for half an hour. It was excruciating. And a helluva lot of fun. I think it was the first time I'd been on a bike in close to a decade, I'm embarrassed to say.
When I was a kid, I went everywhere on my bike. I remember riding it to and from elementary school, riding all over the neighborhood, down to Medi-Park, all over "the fields" (we lived on the western edge of town back then), and basically as far as my parents would let me. Though we did have a few crises, which went very much like what Brian Regan hilariously describes here. ;-)
Riding bikes as a kid was never about exercise, though I'm sure that element was present. It just never crossed my mind at the time. Now, my primary reason to get on a bike was exercise, until I started riding around. Then I found it to be blissful nostalgia. Great memories of times when the world was a much smaller, simpler place.