A fellow's wife was very worried about her husband's heavy drinking and 
one night she decided to give him a fright. She draped herself in a white 
sheet and went down to the local cemetery, knowing that her husband was 
in the habit of taking a shortcut through it on his way home from the 
pub. It was not long before he came staggering along, and out she jumped 
from behind a headstone. "Ooooooo!" she wailed, "I am the Devil!" 

He sticks out his hand..."Put it there, pal," he says, "I am married to 
your sister."