Once there was an older lady that worked in the same building as me while I was in college. She hated my boss, and since I was his protege', hated me. She gave me grief and treated me like I couldn't be trusted even though I was eventually a building manager.
Fast forward to my senior years (I had two of them). A room mate of mine forgot that he put a quart of milk in the back of the refridgerator. Three weeks AFTER its due date I discovered the 2/3 full bloated jug. Instead of throwing it out, we did an experiment. We left it out and periodically released the pressure from the releasing gasses. When it had finally set into chunky cottage cheese and some cloudy water it was done. At the end of the semester, I sneaked a key to her office and emptied the experiment. That was on a Saturday. By Monday morning the entire office complex had a scent to it and her office (which had no windows) reeked so bad they called in some university plumbers to see if a sewage lines had broken. They happened to be friends of mine so I gave them a heads up. When they returned from their "inspection" one told me "Son, I've smelled some pretty foul things in my life as a plumber, but that made me gag." They had professional cleaners steam the carpet 4 times, put every industrial cleaner they could find on it, but to no avail. She smelled foul all summer.
Icing on the cake: my ex-girlfriend worked for her and had a milkshake in there the week before. She was blamed for the whole incident.