So a fella walks into a pub with a biscuit tin and a mouse.
He says to the barman: "Watch this". He sticks the mouse on top of the biscuit tin and it starts dancing.
The barman says: "Blimey, how long does he dance for?"
"As long as you like," said the fella.
"I’ll give you £50 for it" says the barman.
"Sold," said the fella.
That night the fella gets a call from the barman. "How do we stop the mouse dancing, the tapping is driving us mad?"
The fella says: "Lift the lid off the biscuit tin and blow out the candle".