I think I was like 11 or 12 when I heard this ...
Jenny's father was cleaning her bedroom when he found $10 on her dresser. When Jenny came home from school, he asked where she got it from.
"Two boys at school bet me that I couldn't climb all the way up the flagpole!" Jenny replied excitedly.
Jenny's father looked at her dress and immediately knew why ... "Jenny, those boys only pay you to climb up that flagpole so they can see your underwear."
Jenny stared back at him, mouth agape.
"Don't do that any more," he scolded, and left the room feeling satisfied.
The next day, Jenny returned home from school, and her father saw she had $10 in her hand.
"Where did you get that?" he asked suspiciously.
"Those two boys at school bet me that I couldn't climb all the way up the flagpole again!" said Jenny.
Jenny's father was furious. "But I told you, Jenny! They just want to see your underwear!"
Jenny smiled. "But I fooled them, Daddy. I didn't wear any underwear today!"