A blonde girl came home from college one day and told her mother that a boy had paid her a dollar to climb up a ladder and get his ball from off the roof.
"You silly girl," her mother said, "he just wanted you to climb the ladder so he could look up your skirt and see your undies."
The next day the same little girl came home from college and told her mother that the same boy gave her a dollar again to climb a ladder and get his ball off the roof. Just before her mother could admonish her for being silly, the little girl said, "No mum, this time I tricked him. I wasn't wearing any undies!"