This guy was walking down the sidewalk when he sees a Little Johnny
   wearing a red firefighter's hat and sitting in a red wagon which is
   being pulled slowly by a large Labador Retriever. When he got a little
   closer, he saw that the kid was holding a rope which is tied to the
   dog's testicles, which may explain why the dog is walking so slowly.
   Going up to the kid, he said,"That's a nice fire engine you got there,
   but I bet it would go faster if you have the rope around the dog's
   neck."
   "Yeah," the kid replied."But I wouldn't have a siren."