Continuity mistake: During the scene where the Griffins have Tom Brady over for dinner, when we first see the establishing shot of everyone at the table, Chris is sitting with an empty chair between him and Tom. However, when he asks if he can call him Tom along with Lois and Meg, he is sitting right next to Tom, with no empty chair between the two.
Continuity mistake: While Meg is at the kitchen table telling the family about her new life with God, you will notice that Brian is sitting to the right of her. As she starts to ask that everyone hold hands, take notice that Brian is not in that chair and that Brian's plate and utensils are moved closer to Meg. As the shot pans out, Brian is back in that chair.