Mine was back in early 2010, i was happily playing some matchmaking on halo 3, when i felt the need to play some custom games. Unfortuanatly none of my friends were online so i went through the list of people i had recently played with.
I managed to find someone who was in a custom game lobby and quickly joined. After a few games i found out that the guy was a bit of a weirdo, i dont think i can say all of what he was talking about on here so lets just say it wasnt normal swearing...
While we were waiting for a game to start i decided to check out his file share and guess what? it was filled with screenshots, which were threatening and insulting me. not only that but most of them were not even his! this guy i randomly joined, had enough time to gather screenshots with threatening messages and post it on his file share!