Refers to all-out partying, getting wild, and crazier than most people could even imagine. Usually involves getting blacked out drunk and probably heavy drug usage. Someone who regularly particpates in a ragefest apocolypse would laugh in the face of someone who said they were planning on 'raging.' That is considered totally pussy compared to ragefest apocolypse.
Like saying to your friend: "Dude, when we go to Vegas this weekend it's going to be a fucking ragefest apocolypse."