If you lose all your lives or finish the match without killing anyone, finish your drink
The winner of a match gets to deal out a drink to someone, the loser has to take a drink
Alternatively, take a drink relative to your position ie. the winner takes four drinks, 2nd place takes three, 3rd takes two and 4th takes one. The better players receive the handicap of being drunk, so everyone's playing ability levels out fast.
If an explosive spawns on top of you while attacking and then explodes, take a drink out of sadness.
For every KO you score with a hammer/golden hammer, everyone else must take a drink. However, if your hammer breaks/the golden hammer is a fake, or if you kill yourself without killing anyone else while holding a hammer, finish your drink.
If you KO everyone else with the Dragoon, they all must finish their drinks.
If you grab a stopwatch and the only person it slows down is you, take a drink.
Take two drinks every time you accidentally grab a Poison Mushroom, thinking it was a regular one.
For Melee and Brawl: If you SD on the track of Big Blue, take a drink.
For Brawl: If you SD off the left side of the track of big Blue, everyone else takes a drink with you.
For Brawl's Adventure Mode:
Whenever a character's name appears during their first appearance, take a drink.
Whenever a cutscene goes into Bullet Time, take a drink.
If a character says something, take a drink.
Whenever someone is revived from being a trophy, take a drink.
If the trophy is laying down during revival and the revived character is already shown standing instead of getting up, take another drink.
Whenever the Airship theme plays, take a drink.
In every case of Recycled Soundtrack (i.e. a song not newly arranged for the game), take a drink.
Whenever you hear a song that's not in the sound test, take a drink.
Anytime a song plays that isn't in that stage's My Music list, take a drink.