From Just Free Stuff:)

"Andy is driving around Tennessee and he sees a
sign in front of a house:

'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
Labrador Retriever sitting there.

'You talk?' he asks.

'Yep,' the Lab replies.

'So, what's your story?'

The Lab looks up and says, 'Well, I discovered
that I could talk when I
was pretty young.'

'I wanted to help the government, so I told then
CIA about my gift, and
in no time at all 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 eight years
running.'

'But the jetting around really tired me out, and
I knew I wasn't getting
any younger, so I decided to settle down. I
signed up for a job at the
airport to do some undercover security wandering
near suspicious characters
and listening in. I uncovered some incredible
dealings and was awarded a
batch of medals.'

'I got married, had a mess of puppies, and now
I'm just retired.'

The guy is amazed. He goes back in and asks the
owner what he wants for the dog.

'Ten dollars,' the guy says.

'Ten dollars? This dog is amazing. Why on earth
are you selling him so cheap?'

'Because he's a liar. He never did any of that."