A guy walks into a bar with a dog. The bartender stops him, and says that dogs aren't allowed in the bar, and that the dog will have to stay outside.

"But", the guy says, "this is Butch, the talking dog."
"Really", the bartender says (traditional bartender wit).
"OK, I'll prove it. He'll fetch the paper."
"Well, a lot of dogs can do that..."
"And pay for it, and return the change? ", the man says.
The bartender replies, "OK, I've got to see this...."

The man hands the dog a five dollar bill, and tells the dog to go get him a paper.
The dog replies, "OK, boss."
"And, don't forget my change!", the man yells after the dog.

One hour goes by, and the dog hasn't returned.
Two hours go by, and still no dog.
Three hours go by, and the owner is starting to get worried, so he goes out to find the dog.
He looks in the alleyway next to the bar, and sure enough, there is the dog, "in the throws of passion" with a female dog.

"Butch! You've never done this before! Why now?"

"Well, boss", Butch said, "I never had five bucks before".