The manhole
There was a man jumping up and down on a manhole cover saying “49, 49, 49, 49!”
A dumb blond walks up to him and asks, “What are you doing?”
He says, “I’m exercising.”
She asks, “Can I try?”
“Sure.”
She gets on the manhole and does the same thing.
“49, 49, 49, 49!”
The man reaches under her and SNATCHES the cover out from under her, she falls in. He puts the cover back on and jumps up and down on it saying, “50, 50, 50, 50!”