1) Good...
An Erie, PA policeman had a perfect spot to watch for speeders, but
wasn't getting many. Then he discovered the problem. A twelve year
old boy was standing up the road with a hand painted sign, which
read "RADAR TRAP AHEAD." The officer then found a young
accomplice down the road with a sign reading "TIPS" and
a bucket full of money. (And we used to just sell lemonade!).
2) Better...
A motorist was mailed a picture of his car speeding through an
automated radar post in Pittsburgh, PA. A $40 speeding ticket was included.
Being cute, he sent the police department a picture of $40. The police
responded with another mailed photo of handcuffs.
3) Absolute Best...
A young woman was pulled over for speeding. As the Pennsylvania State
Trooper walked to her car window, flipping open his ticket book, she
said "I bet you are going to sell me a ticket to the State Troopers Ball."
He replied, "Pennsylvania State Troopers don't have balls."
There was a moment of silence while she smiled, and
he realized what he'd just said. He then closed his book,
got back in his patrol car and left.
She was laughing too hard to start her car.

Source, perchance?