"Listen," he says to the bartender, "If I show you the most amazing thing you've ever seen, is my beer on the house?"
"We'll see," says the bartender.
So the guy pulls out a hamster and a tiny piano out of a bag, puts them on the bar, and the hamster begins to play.
"Impressive," says the bartender, "but I'll need to see more."
"Hold on," says the man. He then pulls out a bullfrog, and it sings a moving rendition of "Old Man River."
A patron jumps up from his table and shouts "Thats's Absolutely incredible! I'll give you $100 right now for the frog."
"Sold," says the guy. The patron takes the bullfrog and leaves.
"It's none of my business," says the bartender, "but you just gave away a fortune."
"Not really," says the guy, "The hamster is also a vantriloquist."