Weasley family in Egypt

Early in Harry Potter and the Prisoner of Azkaban, Harry sees a newspaper article with a photograph of the Weasley family in Egypt. Though it is never again mentioned in the movie, this is a very important plot point in the book. While on an inspection of Azkaban, the Minister of Magic had a copy of that paper, gave it to Sirius Black, who recognized that Peter Pettigrew was disguised as Scabbers. This is why he decided to break out of Azkaban, track down Scabbers at Hogwarts, and take his revenge by killing him.