When Stewie walks in while Brian is watching The Outlaw Josey Wales, he makes an allusion to Brokeback Mountain when he inquires about the cowboys having sex with each other.
Joe being carried off to sleep on the couch is a reverse parody of An Officer and a Gentleman, with Joe being the navy officer in the arms of his nurse.
Peter tries to emulate Popeye by eating spinach during the fight.
Peter's explains to Lois that physicists believe there are two alternate universes: one where he opens the box, and one where he does not open the box, and subsequently dies. This is a reference to the "Schrödinger's cat" thought experiment, in which a theoretical cat is placed in a box with a device that can randomly kill it. The cat may be simultaneously considered both dead and alive, until the box is opened to reveal the true state.