This is the best (i.e. gets you the most pissed) game I know. Boat Races are ok, but are usually over too quickly as players drop off one by one because they're too full. Century Club always gets everyone fucked, but usually not until the 90 mark. Bastard Darts will get you just as pissed in a quarter of the time. It was initially called Killer Darts, but we renamed it 'cause it's such a bastard.
Needed: dartboard, darts, scoreboard, 200ml (standard glass size) vessels, the more players the better.
To begin, each player throws one dart at the board. The number they hit is "their" number. If they hit someone else's at this stage, they keep throwing until they get a unique one.
Write players' names and numbers on the scoreboard, and give each one ten tally marks (e.g. ||||| |||||) under their name.
Once every player has a number, the game begins. Players stand a specified distance from the board (this should be marked by a spot on the ground or something) and throw their darts (usually three) one at a time. The idea is to hit your own number. If you do so, you consume and wipe a tally mark off your score. Once you have no points left on the board, you are out of the game (this is usually a good thing). The last player left with points has to consume once for each point, in a row. If you hit a double, wipe off two marks and consume twice. A triple, three and thrice.
Now for the fun part. If you hit _someone else's_ number, they ADD points to their score, and consume. Hit a triple, they add three points and consume three times.
If you don't hit any numbers (e.g. miss the board, hit the board but outside the numbers, the dart bounces off the wire) you consume.
If you hit the outer bullseye, you get to allocate one consumption (no points are involved). The inner bullseye is two consumptions (can be one each to two people).
Players must have completed all of their consumptions by their next turn.
The thing that makes this game such a cunt is IT MUST BE PLAYED WITH FULL VESSEL CONSUMPTIONS. Think about it - the minimum you could possibly consume, which you would get by hitting your own numbers, never missing the board, and no-one else ever hitting you, is 2 jugs. But, for no-one to ever hit you, you would probably need to throw 3 triples on your own number, so that's 1.8 litres of consumptions in a row. The more likely situation is that you will go through 2 dozen cans in an hour.
Note that if other people hit your number, you actually have to consume twice - once for the hit and once for the extra point added on. When someone gets a triple of your number, they've given you six consumptions.