Gwyneth Paltrow waved bye to fans yesterday when she left her Venice hotel and hopped into a water taxi. After a stunning few days at the city's film festival in an array of Prada dresses, she was dressed down in a simple top, shorts, and sandals. She had been out earlier, though, in a pink outfit for lunch. Gwyneth and her Contagion costar Matt Damon rose early Saturday for a photo call and then hit the red carpet for a premiere that night. Her husband, Chris Martin, wasn't on hand for the movie fun, but Matt made the rounds with his wife, Luciana, before they, too, left town last night.