I've wondered this for a while.
When did riding on an exercise bike first begin to be referred to as "spinning"? It seems to me that the earlier 00's was the first time I heard this term. A friend kept telling me she was going to her spinning class, and I pictured this room full of people with their arms held out to their sides turning in circles until they got dizzy. Of course, I knew that couldn't be right.
I finally gave up the idea of not wanting to sound stupid and so I asked, and it turned out to simply be everybody riding exercise bicycles.
I am curious about the term, though--does anyone know when and where that first popped up?