Theres all kinds of these...Lets see,
Grease under the door handles
Big Zip ties on the driveshaft-makes hell of a noise under the truck
Simply pushing the transfer case in neutral will cause a brief scare
Fill the cab with packing peanuts
Honey on the steering wheel
Heres my favorite...take a can of regular shaving cream, freeze it, poke a hole in the can, put it in someones toolbox...As it thaws, it fills most of the toolbox with cream. Its funny when it starts spewing out of the drawers.
Theres more, cant think. I've done all of these. Most people i know have nice trucks...and then theres the beater they drive to work. This kind of stuff only gets done to the beaters. Kind of an unwritten rule.
I've also piled 5ft of snow around peoples vehicles with a bobcat or put thier car on top of a container with a forklift, chained them to a guardrail, put cars on jackstands...had it all done to me too so dont go thinking i'm the a**hole. all in good fun.