A guy walks into a bar. He tells the bartender he has no money, but in exchange for a beer he'll show him a trick he'll never forget.

The bartender shakes his head but goes ahead and gives the man a beer.

The guy takes a rat out of one pocket and a frog out of another. The rat scurries over to the bar's piano and plays a tune. The frog belts out the song in perfect harmony with the rat's piano playing.

A few minutes later another man walks over and offers the customer $100 for the frog. He instantly accepts, and gives the other man the frog.

"Are you nuts?" the bartender asks. "That frog could be worth a fortune to you."

"Don't be so sure," the customer says. "The rat's a ventriloquist."