Glenn Howerton, who plays Dennis Reynolds in 'It's Always Sunny in Philadelphia' has a cameo as Dominic, the guy sent to negotiate with the nuns. Later in the film when Officer Gable follows Officer Downe to his girlfriend's apartment, the building Downe parks in front of is the same building used for exterior shots of Paddy's Pub in 'It's Always Sunny in Philadelphia.'
Corey Taylor, singer for Stone Sour and Slipknot, also stars.
The director is also known from the band Slipknot (Clown, #6), as one of the two custom percussionists and co-founder.
Shawn Crahan, The Director, is Clown from the metal band Slipknot
In the bar scene the "Rook" is wearing a CBC (Canadian Broadcasting Corporation, the Canadian government public broadcaster) t-shirt...