Anyway, I was DMing a D20 Future game(cyberpunk, aliens, mutants, the works) and at the start of the game I told the players that their characters grew up together, so they could pull out things that the other characters would recognize(though their players would not at first). Little did I know that this would cause some very interesting things to happen. One thing I try for is that everything they say is IC, unless they do or say something that shows that they're OOC(usually a T with their hands or something).
One major "background event" occurred during the opening session that lasted for quite awhile. The first was this.
One player(henceforth PC A, male player, female character) said: "Come on, this will be fun."
Another player(PC B, male player, male character), in RL, simply looked at PC A and replied: "That's what you said about the chicken suit and gun."
Now this is where I have to give PC A credit. He barely blinks at this(I'm sitting there thinking 'what is this guy on? chicken suit?'), and replies: "Oh come on, you liked what I gave you last time."
At this point everyone breaks out laughing, and we return to the game. But several weeks later, the characters get given a "hunt and kill" mission, and the target ran into a crowded amusement park(hostage work at it's best). So in after him the PCs go. Well, they find him, but can't get to him since he's been alerted to them being there. They duck into a nearby closet in order to discuss. Finally one PC slips out and comes back with several packages, which turns out to be costumes, including (you guessed it!) a chicken suit.
You know, in hindsight that isn't very funny, but at the time it was absolutely hilarious. I still find it quite amusing. That's about it for now. Nice to meet you all.