A circus owner walked into a bar to see everyone crowded around 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, 
"Your duck is a rip-off! I put him on the pot before a whole audience and he didn't dance a single step!" "So?" asked the duck's former owner, 

"did you remember to light the candle under the pot?"