A term normally found on college campuses, the title became popular when many people did not have early morning classes on Fridays, allowing them to drink and party on Thursday night. Every Thursday of every week durring the semester is Thirsty Thursday; there is no specific or special date for it.

I couldn’t care less (but one must keep up appearances, right?)

Pioneered by business school students who don't have class on friday like everyone else. Thirsty Thursday's is the worship of the gods of alcohol intoxication with limited consequences. Most important at colleges with a high commuter to on campus population ratio.

The big party night at colleges. Who cares about class on friday?

When you have to party on Thursday because the week is stressing you out enough already, or just because

An early start to the weekend for many college students who go out and get sloppy on Thursday night.

The term orginated in bars to promote specials but is now most often used as a day when college students get drunk.