Paint the Porch
A blonde moves to Beverly Hills, hoping to find an acting job. After a couple weeks with no luck, she decides to go around to some of the rich people's houses and see if she can do some odd jobs for them to make a little money. She finally goes to one house, and a guy and his wife come to the door. "Sure, I have a job for you," says the guy, "You can paint my porch. How much money do you want?" The blonde thinks about it and says "I can do it in less than an hour. Twenty bucks!"
The guy says "Fine, there's a gallon can of paint and a brush in the garage, let me know when you're finished." So off she goes to the garage.
The guy's wife says to him "Fred, that wasn't fair, you tricked the poor girl. She doesn't realize the porch runs around the corner all down the west side of the house to the deck. It'll take her the whole day!"
"Too bad!," he says, "Maybe that dumb blonde will learn a lesson."
An hour later, the blonde is at the door again: "All Finished! And I had enough paint to put on a second coat! Oh, and by the way: that's a Ferrari you have there, not a Porsche. Duuhhhhh!"