An old man goes into a pharmacy, asks for two Viagra pills and demands that the pharmacist cut them in half.
The pharmacist winks at him, “OK, but do you realize they won’t be as effective?”
The old man says, “Listen sonny, I’m 80 years old. I don’t want them for sex but to get me hard enough so I don’t pee on my shoes. “
This joke is included in the Black Book of Jokes. You can order it from here.