A man sees a sign in front of a house that reads "Talking Dog for Sale." He rings the bell and the owner tells him the dog is in the backyard. The guy goes into the backyard and sees a black mutt sitting there.

"Can you really talk?" the man asks.

"Sure can," the mutt replies.

"So, what's your story?"

The mutt looks up and says, "Well, I discovered my talking ability pretty young and I wanted to help the government. So I told the CIA about my gift, and in no time they had me jetting from country to country, sitting in rooms with spies and world leaders, because no one figured a dog would be eavesdropping.

"I was one of their most valuable spies for five years running. The travel really tired me out, and I knew I wasn't getting any younger, so I decided to settle down. I took a job at the airport and did undercover security work: mostly wandering near suspicious characters and listening in. I uncovered some incredible dealings there and was awarded several medals.

"In between all of this, I got married, fathered a bunch of pups, and now I'm retired."

The guy is amazed. He goes back and asks the owner how much he wants for the dog. The owner says, "Ten dollars."

The guy says, "Ten bucks? Why, this dog is incredible! Why in the world are you selling him so cheap?"

The owner replies, "He's such a liar. He didn't do any of that stuff."