I'm Her Brother

At a girl's college dormitory, dates were permitted only on Saturday night. One young man showed up on a Tuesday evening, explaining to an older woman in the lobby of the dorm that it was imperative he see a certain young lady immediately. "I want to surprise her. You see, I'm her brother." "Oh, she'll be surprised all right," said the woman. "But think of how surprised I am, I'm her mother!"