It was nearly the end of one of David Copperfield's magic shows.
"Now," he said, "We've reached the part of the show where I invite a member of the audience to come up on stage and perform a trick. Are there any volunteers?"
The audience shuffled in its seats.
"Oh come on, *someone* must have a party piece to show us!"
Slowly a hand went up.
"Yes, you, sir!" beamed Copperfield. "Please join me on stage!"
A huge sweaty bald guy heaved himself out of his seat and lumbered up onto the stage.
"For this trick, Dave," he said, "I'll need a table, a length of rope and Claudia Schiffer."
The props were brought on, as was Claudia, looking as stunning as ever and giggling girlishly.
The fat sweaty guy quickly tied Claudia down to the table, lifted her dress, pulled out his old man and started pumping away.
"Hey!" yelled Copperfield, "This isn't a goddamned trick!"
"No," replied the fat guy breathlessly, "But it's ****ing magic!"