My sister found this on Socially Retarded. It's another message board type place. Anyhow, there is a thread started named "What is the meanest thing you ever did ?" Most of them are kinda stupid, but there are a couple of gems in there:
"I had a neighbor who was really getting on my nerves. He would yell at my kids, call the cops on us etc. One night I was drunk and courageous and I got the idea to shove some exlax in a hot dog and threw it over the fence to his dog. I heard from another neighbor that the dog **** all over the carpet inside."
"My obsessive, neat-freak, soon to be ex-roomate always flipped if anything was out of place, and would 'punish' me for it by, for example, unhooking the phone and locking it in his room. The day I moved out I filled his Brita with toilet water from the toilet I refused to clean!"
Be warned though most are stupid