Fittings in their hubcaps
duct tape flap on their driveshaft
silicone grease under the door handles
Take pictures of their truck and put an ad on craigslist for $200 with their phone number
Go to the stoner-hippie store and buy some rainbow stickers and put it on their truck.
Fish in the air conditioner
Spooge silicone sealant into their doorlocks
Tie the bumper off to their garage door with RG-11
Post pedo pics of them all over their neighborhood
Call the dick [vag/breast] doctor and make them an appointment for ED[tightening/enlargement] consultation
the list goes on...