One of my suite's previous residents left this in my commons room, and my God are the possibilities endless. A few that I came up with whilst imprisoned on the uptown A train (keeping in mind that I don't actually, like, recommend trying these. This is a thought experiment ONLY. Repeat: a thought experiment ONLY.):

RULE: When a piece is taken, its owner drinks it.
STRATEGIC IMPLICATIONS: Rewards aggressive gameplay, especially if your opponent is a lightweight. Alters the opportunity cost of a piece swap: if one more shot will put your opponent over the edge, an otherwise-misguided castle-for-knight exchange might not look so bad.
PRACTICAL EFFECT ON GAMEPLAY: Could lead to lopsided victories, since weaker players will be both drunk and behind on pieces. The potential "pro" side of this is that it will definitely lead to weaker players getting really, really drunk.

RULE: When a piece is taken, the player who took that piece drinks it.
STRATEGIC IMPLICATIONS: If you're both a lightweight and a stronger player, you have a certain incentive to win quickly--and without drawing your opponent into an excruciatingly mid-game. Weaker players could also throw away pieces with the intent of getting a stronger opponent drunk, although that strategy depends on a lighter drinker falling for his opponent's gambit. Of course a bit of alcohol tolerance makes it so that none of this really matters--especially if you can wrap up a game before you start to brown out.
PRACTICAL EFFECT ON GAMEPLAY: Rule could act as an equalizer, since better players will get drunk faster. Of course better players will also figure out a way to win without mowing down all of their opponents' pieces, so the effect is, perhaps, ambiguous. Too bad this is just a thought experiment, and shouldn't be tried in real life...

RULE: Whenever a knight jumps an opposing piece, its owner drinks the piece.
STRATEGIC IMPLICATIONS: Instantly makes the knight the most important piece on the board. Knight play is one of those things that separates dilettantes from serious players, and this rule greatly favors the rare amateur player who really knows how to use them. This also makes the knight-for-bishop a total raw deal, which means that the pieces' strategic value is no longer equivalent (not that they really were in the first place, but for argument's sake...)
PRACTICAL EFFECT ON GAMEPLAY: Could turn the game into a race to see who can set up the most aggressive knight-queen-bishop combo. Could also turn the game into a dueling set of knight's tours, which could be kinda exciting.

RULE: Loser drinks every piece. Needless to say, players should fill their pieces with the weakest stuff they can find (as they should for all of these games, come to think of it...if these games were meant to be played in real life, that is)
STRATEIGIC IMPLICATIONS: With an entire night of lucency potentially on the line, I imagine both players would proceed verrrrrry carefully.
PRACTICAL EFFECT ON GAMEPLAY: Turns every move into a monumental, life-or-death decision--perfect for those who enjoy three-hour dogfights.

Any more you can think of? Post below!