Move The Car
When your victim isn't paying attention. Get his keys and move his car. If he parked out in the street next to the curb. Then just turn the car around so it is now parked the wrong way.

Tire Blowout
Place a blown up balloon under your victim's tire. When he starts the car up and drives off, he will hear a loud POP!! and think the tire just blew out!

Confetti In The Defrost
Pour some confetti in your victim's defrost vent and turn it on high. When you starts the car up the next day, it will be like New Year's Day all over again.

Bumper Sticker Prank
Know someone who supports PETA? or loves and helps protect the environment? or maybe the person is a homophobe. Well just place a bumper sticker on his or her ride that gives the opposite message such as "I love KFC chicken" (for PETA supporter) or a rainbow sticker that reads "Gay and Proud" or for the environmentalist, have it say something like "I favor oil fields over rain forests"

Fake Company Sign
Place a fake company sign on the side of your victim's vehicle. Have the sign read something like: "Handy Auto Wash - The Best Hand Jobs in Town. Be creative use a company and slogan that would get alot of looks.

Long Road Trip Gag
Have some fun on your next road trip. When your passenger falls asleep and is leaning on the right front window. Try this, quickly jerk the car from right to left then back. Then watch your victim's head bounce back and forth against the window.

Wrong Directions
Mess around with a victim who has aleady wrote directions down. When he or she isn't looking change the directions to send them in the opposite direction.

Frozen Balls
In the winter time, when its freezing outside...dip some cotton balls in water and place them all over your victim's car.

Adjustable Mirrors
While your victim is driving and you are the passenger adjust the side mirror. After awhile it will annoy the driver.

Drag n Drive
attach a fishing line with objects to the rear bumper of your victim's car. When he drive off, he will be dragging items along with him.