There was a young country boy who was very bright.
In fact he was bright enough to be accepted to Oxford University.
One of his first assignments at Oxford was to write a paper on a famous person. He didn't know who he would write about so he decided to go to the library and do some research. But he didn't know where the library was. He saw a professor walking down the hall.
He stopped the professor and said to him, "Do you know where the library is at?"
The professor looks at him strangely and says, "Young man, here at Harvard we never end a sentence in a preposition."
The young man says, "Oh, excuse me. Do you know where the library is at, asshole?"