Amy, a blonde a city girl, marries a farmer. One morning, before he goes
out to the fields, the farmer says to her,
"The artificial insemination  man is coming to impregnate one of our cows
today.
I drove a nail into  the two-by-four above the cow's stall. You show him
where it is, okay?"

So the farmer leaves for the fields, and a while later, the artificial
insemination man arrives. Amy takes him down the long row of cows until
she sees the  nail, and tells him, "This is the one. This one right here!"

Terribly  impressed, the man asks, "How did you know this is the cow to be
bred?"

"By the nail over it's stall," Amy explains. Then the man asks, "What's
the nail for?"

"I guess it's to hang your pants on," she says, as she  walks away