Usually played, just prior, to heading out to the bars & clubs (A.K.A. "pre-game drinking" or "pre-gaming").
RULES: using an egg timer, or clock... every participant drinks a completely full shot glass of beer every minute, on the minute.
This game is used as an easy way to get a quick "buzz"... yet difficult (for some) due to the constant smaller quantities of alcohol, timing, and aeration of the beer.
SEE: "Power Hour" for a longer version of this game.
Person B: "No. Let's watch the end of the game, then head out to the bars."
Person C: "I want a good buzz before we leave..."
Person B: "Let's do a Dirty Thirty, then head out to the bars!"
The expression almost always refers to women, as men are thought to always be in this state.
"Alright Ladies, this dirty thirty is on the house!"
Leo: No, I can't drink, there are exams this week.
Jimmy: No, I mean the dirty thirty from Nafer.