A man walks into the bar and sits down. The bartender asks him what he wants, and the man replies "I'd love a beer, however I don't have any money."
The bartender sighs, and says "Ok, fine. Just show me something amazing, and I'll give you a beer on the house."
The man reaches into his briefcase, pulls out a frog and a tiny piano, and sets them on the bar. The frog hops onto the tiny bench and starts playing.
"Oh my god, that's amazing!" says the bartender, and hands the man a beer.
A little while later, the man has finished his beer, and the bartender asks him if there's anything else he can get him.
"I'd really love another beer, but I still don't have any money."
"Well, if you can top what you've already showed me, I'll give you another beer."
The man reaches into his briefcase again, pulls out a mouse, and sets the mouse on the tiny piano. The frog starts playing, and shortly thereafter, the mouse begins singing beatifully.
"Wow, that's incredible!" says the bartender, and hands the man another beer.
Another man sitting at the bar approaches and tells the man "That's unbelievable, I'll give you $5,000 right now for your animals!"
The man ponders the offer, and replies "well, I'm a bit attached to the frog, but how about the mouse for $3,000?"
"Deal!" says the other man, who pays, takes his mouse, and leaves.
The bartender says "man, you could have made so much more than that off of that mouse, why did you sell it for $3,000?"
"Because," says the man, "the frog's also a ventriloquist."