Ben Affleck and Jennifer Garner made a special trip to the post office in LA today with their son, Samuel. Samuel was tucked away in his carrier for the family outing. Ben's been sticking close to home with the little guy lately, but he'll soon get started on his next project, Runner, Runner. Runner, Runner is already filming in Puerto Rico and his costar Justin Timberlake has been spotted on set this week. Justin's fiancée, Jessica Biel, joined him on the island, and spent one afternoon on the beach in her bikini. Ben might bring his loved ones along, too, which could mean plenty of fun in the sun for Jennifer, Violet, Seraphina, and Samuel.