A circus owner walked into a bar to find everyone crowded about a table watching a little show.
On the table was an upside-down pot and a duck tap dancing on it.
The circus owner was so impressed that he offered to buy the duck from its owner.
After some wheeling and dealing they settled for $10,000 for the duck and the pot.
Three days later the circus owner runs back to the bar in anger, shouting “Your duck is a rip-off! I put him on the pot before a whole audience and he didn’t dance a single step!”
“That’s strange” said the duck’s former owner, “did you remember to light the candle under the pot?”
Image used under a Collective Commons License from: https://commons.wikimedia.org/wiki/File:White_domesticated_duck,_stretching.jpg