A man walks into a market followed by his ten-year-old son. The kid is spinning a 20 cent coin in the air and catching it between his teeth.
As they walk through the market someone bumps into the boy at just the wrong moment and the coin goes straight into his mouth and lodges in his throat.
He immediately starts choking and going blue in the face and Dad starts panicking, shouting and screaming for help.
A middle-aged, fairly unnoticeable man in a grey suit is sitting at a coffee bar in the market reading his newspaper and sipping a cup of coffee.
At the sound of the commotion, he looks up, puts his coffee cup down on the saucer, neatly folds his newspaper and places it on the counter. He gets up from his seat and makes his unhurried way across the market.
Reaching the boy, the man carefully takes hold of the kid's balls and squeezes gently but firmly.
After a few seconds the boy convulses violently and coughs up the 20 cent piece, which the man catches in his free hand. Releasing the boy, the man hands the coin to the father and walks back to his seat in the coffee bar without saying a word.
As soon as he is sure that his son has suffered no lasting ill-effects, the father rushes over to the man and starts effusively thanking him saying: "I've never seen anybody do anything like that before - it's fantastic - Are you a doctor?"
"Oh, good heavens, no," the man replies, "I work for the Australian Taxation Office".
(Aside: clearly this is not a true story. A real ATO employee would have kept the money.)