Blood Bank
A man and a woman got in an elevator at the same time one day. The man asked the woman which floor she wanted.
"Second floor", she said, "They're paying 25 dollars a pint at the blood bank".
The man replied, "I'm going to the fourth. They pay 200 dollars an ounce at the sperm bank".
A week later the man and woman both got on the same elevator again. The man, recognizing the woman asked, "Second floor?".
With her mouth closed and her cheeks puffed out, she just shook her head and held up four fingers.