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 got melee'd (killed by melee), three drinks
- Conversely, if you score melee kill, everyone else drink
- 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 this from other players, take a sip and hope you still have the use of your legs at the end of the match
- 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.
For singleplayer:
Take a sip:
- Upon being killed by bullets (good luck on Veteran)
- Upon switching weapons
- In Modern Warfare 2, every time someone yells at Ramirez to do something. Can be extended to any player character if you really hate your liver.
Take a shot:
- Upon completing a level
- Upon being killed by a grenade. You're going to need a cast iron stomach and maybe a cast iron pot and stomach pump.
- Upon finding an intel item
- Upon using any kind of heavy weaponry (rocket launchers, UAV support, C4 charges, mounted guns)
Take a drink:
- Upon Sarah Michelle Gellar making a Buffy the Vampire Slayer reference.
- Upon the a war crime scene.
- Upon the game delivering a Player Punch. If it's the big one for the game, finish the six pack or mixer bottle and get another one.
- Upon being tasked with saving the President's daughter.