The Biker
This biker goes to the county fair. He spends some time looking at the sideshows, wondering what to have some fun with, when he sees a bucking bronco machine, and decides to take a crack at it. So he gets on the machine, and its operator sets the controls to '3'. Off the machine goes with the biker on the back screaming and shouting and waving his hat in the air.
"Heck, we've got a right film star here" thinks the machine's operator. "I'll soon get rid of this clown!" So he whacks the controls up to '7', then '8' and finally '10'. Still the biker is riding away on top of the machine. After about 5 more minutes, the machine's operator realises that he's *never* going to get rid of this guy, so he shuts the machine down and goes running over to talk.
"You've done this before, haven't you?"
"No, never"
"How come you're so dammned good at it then?"
"I've really no idea..." The biker paused, "Mind you, my wife has epilepsy.."