There's Something About Paulie - S2-E16
Continuity mistake: When Meg is explaining why they can't do Death of a Salesman in school, Lois is lying on the couch with her feet visible. Peter is not shown in this shot, but just before, he was standing behind the couch. Then, in the next shot, suddenly Lois is sitting upright and Peter is sitting on the couch right next to her. (00:01:10)