“Pawn Stars,” which debuted in June 2009, marks its 500th show this month. The broadcast is set for Jan. 22. Rick Harrison asks, “Who wants to watch a show about four fat guys working at a pawn shop?” But the owner of Gold & Silver Pawn has helped turn his father, Richard; son, Corey; and Austin “Chumlee” Russell into TV stars. From The Colosseum at Caesars Palace … Celine Dion had to cancel a weekend show. She said in a statement on Twitter she was resting, under doctor’s orders. On New Year’s Eve, she welcomed the idea of a duet with Lady Gaga. As Celine says, “I would love I would love that. I love her so much.”