A Very Special Family Guy Freakin' Christmas - S3-E16
Continuity mistake: When Peter is driving, Quagmire is sitting beside him and Cleveland and Joe are in the back seat. Joe has brown hair and he's wearing a gray knit hat and a light coat with a gray fur collar. When Quagmire is sticking his body out of the car door and yelling "Whooooooa! Whoooooooa!", look at "Joe" in the back seat. Joe doesn't look like Joe in this shot. He's wearing a Santa hat and a brown coat just like Quagmire's, and a bit of his hair is also black like Quagmire's, instead of brown. (00:05:30)