Recently, my brother and I were trying out the multiplayer in GTA IV for the first time (my brother lives in Wales, I live in Chicago.) Of course we originally intended to do one of the multiplayer games, but our faffing about was much too fun to be bothered with any organised mission. Anyway, we were at a baseball diamond attempting to play baseball with a live grenade: one person cooks grenades and throws it at the bases, the other is in a car at home and must round the bases without getting blown up.
After doing this a few times we were both rolling with laughter (and Guinness) at ourselves and it was my turn to lob grenades. I asked my brother if he was ready, and he said, "Sure, toss me off." Being the cheeky bastard that I am, I quickly switched to the RPG and threw him a strike in the form of an exploding-car-curve-ball.
I haven't laughed so hard with him since we had a crayon war with our neighbours many, many years ago.