When Sam, Dean, Bobby and Castiel are sitting in the diner and Castiel realizes he has no powers, Dean calls him a "baby in a trench coat". Castiel reacts by turning and looking out of the window. This was not scripted, but happened because Misha Collins (Castiel) forgot his lines, which is why the others looked so confused.
When Dean says, "beat me with a wire hanger, the answer's still no," this is a reference to the film on which the title is based, Mommie Dearest (1981).
In the bar full of dead hybrid monsters, Dean mentions the Motaba virus. In the medical horror movie Outbreak (1995), the Motaba virus is an impossibly contagious, 100% fatal hemorrhagic fever that makes Ebola look mild.
The nametag Eve is wearing in the diner says "Angela", the female version of "Angel".