I wonder if this is as common a thing in the UK as dreaming of the royal family?
Incidentally, I wonder about the history of this habit. People couldn't imitate commentaries before there were commentaries, after all. I remember in Ian McEwan's Atonement the little girl Briony swipes the heads of dandelions with a stick (or something similar) and imagines someone commentating on her as if she were at the Olympic Dandelion Beheading final. That would be in the late 1930s. By that time there was certainly radio commentary on football, and I daresay cricket and horseracing too. Live coverage of the Olympics, though? I'm not sure. And, before Marconi, were our imaginations mute?