Of course these basic rules can be applied to most FPS which have split screen multiplayer.
* If you die, drink
** If you're killed by a headshot, take two drinks
* If you use a killstreak reward, take a drink
* If you insult or abuse another player (for example, say you slept with their mother, call them a "*@#!", teabag their corpse), take a drink
* If you hear a character say oorah, or some derivative thereof, then take a drink.
* If you pick up a new weapon, drink.
** If you change class, drink. Choose wisely.
* Every time you're killed by lagging out, take a drink.
Take a sip:
* Upon being killed by bullets (good luck on Veteran)
* Upon switching weapons
Take a shot:
* Upon completing a level
* Upon being killed by a grenade
* Upon finding an intel item
* Upon using any kind of heavy weaponry (rocket launchers, UAV support, C4 charges, mounted guns)