A blonde was driving her car one day, when she ran into a hailstorm. The hail stones were very large and made a lot of dents in the roof of her car. After the hail stopped, she went to a gas station and asked the attendant what she could do to get the dents out of her car.
The attendant, being a wise guy, told her: "Blow real hard into the exhaust pipe, and that should push out the dents."
When the blonde got home, not knowing any better, she did just that.
While she was down on her hands and knees with her lips wrapped around her car's tailpipe, huffing and puffing trying to blow the dents out, her roommate, also a blonde, came home.
Her roommate, of course, asked her what the heck she was doing.
The first blonde told her how the guy at the gas station said this was how she could get the dents out.
The second blonde thought about it for a moment, then said: "Like, uh, you have to roll-up the windows first."