Graveyard Hour
The last few hours of the night (i.e. 6am-8am) when most people have left the club, and those that are left are seriously monging out. Dance floor is sparse and holds resemblance to a grave yard.
"What time's your mate playing tonight?"
"Not until the graveyard hour, we'll probably have gone home by then."
"Not until the graveyard hour, we'll probably have gone home by then."