The time that a party really "begins", no matter what scheduled time the party was actually supposed to start previous. This is the time that, without fail, droves of people show up all at once and a party can go from almost non-existent to full-fledged rager.
"Man, this party was so lame for like the past 3 hours, now it's insane! (Looking down at watch, seeing it's around 11 PM) 11 O'Clock Rule, happens every time!"
by Matty Rob April 6, 2009
You have to take me home
But what am i going to do if i am not drunk before eleven
So you have to get drunk before 11
Yeah its the 11 o'clock rule
But what am i going to do if i am not drunk before eleven
So you have to get drunk before 11
Yeah its the 11 o'clock rule
by burnt cracker March 17, 2010