My friends and I play a sort-of similar game year-round, which one of us decided to call "Gaijin Tsujiguri" after reading a cracked article, and no other official name has been suggested since. The rules are, whenever you pull out an invisible katana (extra blood grooves) and "decapitate" the other guy while saying/yelling/singing "DECAPITATION!" like Eddie Riggs from Brutal Legend, you get 2 points of honor. Whenever you get decapitated, you lose one honor. However, there are many weapons, some of them highly magical, others merely convenient, (and most of them completely fucking made up on the spot) with a whole myriad of different rules applied to them. Here are a few of the simpler ones... The ones that don't lead to hour-long discourses on whether or not this thing vs. that thing would actually work the way one or both wielders intended:
The Naginata: (Pretend you're holding a spear and say "Naginata!") The same thing as the Katana, except you can decapitate someone from a longer distance.
The Baton: (Hold your arm perpendicular to the opponent's swing and say, "Baton!") It's made out of something generally believed to be indestructible to most other weapons that aren't specifically said to be baton-shattering beforehand. (It takes longer to say "Baton-shattering <weapon name>!", so nobody uses it unless they're absolutely sure, since, y'know, decapitation only happens to the opponent if you finish saying the activation phrase before the other guy.) It blocks the katana, and then you knock the other guy out, giving you an additional honor point for mercy. The drawback is that you can only baton people who attack you first, because otherwise your arm gets sliced off and you can't attack again until you get decapitated and "respawn" in the next class. (a fate worse than actual decapitation.
Morton's Fork: (Hold up two fingers and say, "Morton's Fork".) You actually lose honor (both in-game and irl) for using this weapon, because it's kind a dick move, but everyone around you dies and loses honor too, because it works well only for the wielder and completely fucks over everyone else nearby, no matter what improvised spells and weapons they pull out their ass. It's useful when you're ahead of the game and everyone else gangs up on you.
The Flying Guillotine: (Say "Flying Guillotine!" after you've been decapitated) A magical weapon that you can fill with your spirit after decapitation, which flies out and decapitates the person who decapitated you, takes their soul and in the meantime reconstructs your body so you can catch it when it comes back around.
Flaming Shield Throw: (Say "Flaming shield throw!" and throw an invisible frisbee.) It was inspired by Berkazerka, and pretty much works like the baton, except at longer distances. (You can block ranged weapons and naginatas with the baton, but you can't knock them out unless you're close.) Since you won't get your arm cut off if you're blocking from a distance, the drawback is that you only get one honor per kill, because breaking someone's bones and then letting them burn to death isn't as humane as just decapitating them. It can be used to squeeze additional points out of Flying Guillotine users.
Claymore: (Swing like Braveheart and say "BIG FUCKIN' SWORD, LAD!" as hammily as possible.) Too heavy to be blocked by a baton or flying shield and able to knock most thrown weapons away, the Claymore basically fucks up pretty much everything, at the expense of taking longer to say than "Decapitation".
There's also gimmicks like "Re-capitation", "Steal", "Shaolin Shit", "She-Capitation", "Summon Thing" and "Summon Bigger Thing" that can be cast more times a day the more honor you have, which can turn things on their head and make the game a very dangerous one indeed, especially when 4-5 people are playing and we all get into the hallways at roughly the same time.
Whoever gets the most honor in a day wins the day, whoever wins the most days in a month wins the war, and therefore receives any and all the land, cows, heirs, peasants, crops, rent, discount trading goods, and wives that the other players might have. Then the game resets. I'm usually the winner for about 6 months in a year, February is an absolute clusterfuck, and I usually pull things out of the gutter by June, which allows me to leave the school with everyone else's imaginary spoils.