We've got tons of them, from all kinds of sources. In-jokes are a way of life, it seems.
Anyway, our most venerable and relevant gaming in-jokes are "Camp Happy," "I sit in my dinghy and hold my action," and "...the one not closest to me!"
The first one is from the AD&D2 game I played in during high school. My good friend Chris was playing a really obnoxious magic user, and had just gotten to the point where he could cast Fireball. And as we all know, when your mage has just learned Fireball, everything looks flammable.
So we're breaking camp in a forest when a random encounter table strikes, and we're presented with a handful of hill giants going somewhere. Chris grins and starts counting out some d6s, but gets interrupted. The hill giants are waving to us. In a friendly kind of way.
We chat with the giants for a bit, and they're not looking for any trouble. The various good or good-tempered characters are having a wonderful time just gabbing away with these guys, trading rumors and comparing maps, and the entire time Chris is scowling. "Look," he finally interrupts angrily, "don't you have somewhere you need to be right now? Why are you wasting our time like this?"
One of the giants looks at another PC and says, "He seems upset."
Now Chris explodes with fury: "I'm not upset! I'm perfectly happy! Everyone here is happy! This is CAMP F-CKING HAPPY! NOW GO AWAY!"
Later, we named the building in Myth Drannor we were fortifying as a safe campsite "Camp Happy," and even put up a sign outside describing it as such.
...Chris, naturally, cast an Exploding Runes spell on that sign. Just in case any more giants or other nonhostile creatures decided they wanted to stop by for tea.
By now, "Camp Happy" gets namedropped for campsites we've spent too much time talking about, elaborate fortress-like schemes for defending buildings, or meandering in-character PC-NPC chitchat that is keeping us from moving on with our plans. None of the original players of that game are still around (except for me...I alone am left to tell the tale!...er, sorry), but the in-joke still survives.
"I sit in my dinghy and hold my action" isn't from any game we ever played in; we stole it brazenly from a list of funny gaming quotes we found on USENET sometime around 1992. It's from someone else's Champions game, where they had a big blowout undersea battle and the only character who couldn't breathe underwater was the laconic Texas gunslinger. As the battle raged on and the hours passed, every time his turn came up the gunslinger's player would announce in a loud Texan drawl, "Ah sit in mah dinghy, and ah hold mah action."
Since then, it's been acceptable in our group to just say "I sit in my dinghy" if you're holding for something.
The last one's from a 7th Sea game, and it's partly the GM's fault but mostly mine. I was playing a ridiculously swashbuckly Castillan swordsman, and I was sneaking around a manor with a less-skilled Montaigne swordsman. We hear guards coming, and prepare an ambush in a nearby room, but the only way it'll work is if we're both on the same side of the door.
So in come the guards, and it's time for us to declare who we're going to target. The Montaigne player, naturally, says "I attack the one closest to me."
I bravely say "I attack the one NOT closest to me." And the GM nods and says, "You attack the one closest to him, then?"
Now I'm puzzled. "No!" I reply, and I'm told that I sounded like a teacher rebuking a preschooler with his tongue in the paste jar. "I attack the one NOT CLOSEST TO ME."
This is the GM's cue to repeat the same question, only with more disbelief. We take this merry-go-round for another spin, and finally it occurs to the Montaigne swordsman's player to interject a cautious "I think he wants to attack the guy I'm not attacking."
"YES!" I say, privately wondering why I didn't just say that in the first place. Y'see, I was imagining a situation in which the guard closest to the Montaigne swordsman was ALSO the one closest to my Castillan swordsman, and since my character was ridiculously nimble, all I was trying to do was make sure that I was the one who had to move the furthest to get the fight started. The GM, of course, had pictured it entirely differently, and neither of us knew what the hell the other one was thinking. Later, we both admitted that we were dolts, but it was too late: posterity had claimed the story for its own, and the word "closest" itself became funny to us.
So now it's just a running gag, something that gets trotted out whenever someone is particularly unclear about who they're targeting. Happens at least once a session.
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our gm's wife has pointed out that we have a whole language built out of in-jokes
ryan