I have two that aren't mine, but one is fucked up and one is funny.
In college, a dude left his car parked at our house. My buddy shaves his pubes, crawls through the sunroof, and stuffs the pubes in the AC vents and turns them on high. When the dude got in his car and turned it on, boom, pubes/body hair all in his face.
The other, was another guy I went to college with, but not good friends with him by this time. He delivered pizza to make money. He kept a log book of his deliveries, like who had good shit at their house he could steal later, who didn't tip etc. Well, these one people lived in the boonies, and would never tip well. One time they tipped him $.12, the change for the order. So, he writes down the address. Next time they order, he takes the pizza in the bathroom, takes a shit, and runs doodoo paper all over it. Some fucked up shit, and I know the kid did it by knowing his personality. I always tip the driver.
I have some cool personal ones I'll post when I get a minute. Typing this on my phone in the shitter now.