Just when we thought we'd seen every square inch of Kim Kardashian, she gives the world a peek at her butt crack.The reality queen shared a pic of herself perched on mussed sheets in a recent Instagram shot. A cup of coffee balances perilously close to her famous and totally bare derriere. All she revealed about this shot is that it's part of a "secret project" she's working on.But the cat is already out of the bag. Because being Kim Kardashian pretty much means that you only have secrets until you figure out a reveal that will catapult you further up Fame Mountain. This pic, which was snapped by photography power duo Mert Alas and Marcus Piggott, is likely linked to a W magazine feature that captures celebrities in bed