A time in the evening when it's very late, you are very trashed, and the end of your night is approaching. Usually a time of the evening when your condition allows you to make bad choices.
Guy 1: "I think that chick at the end of the bar wants to go home with me..."

Guy 2: "Man, she is really hit... It must be twelve dark thirty...
by larryj March 13, 2010
Get the twelve dark thirty mug.