You'll need a deck of cards.
Choose someone to be the dealer. The dealer starts by dealing a card face up to the player on their left. That player must then guess whether the next card will be higher or lower than the card they've been dealt.
If the player guesses incorrectly they must drink a number of fingers equal to the difference between the two cards.
If the player guesses correctly, or if the second card has the same rank as the first, then they play again.
If a player survives three rounds they nominate another player to drink, and also get to make a new rule. Play passes to the next player if a player guesses incorrectly, or if they manage to survive three rounds.