A Presidential Event...

President Obama is gearing up for another late night talk show visit. The president will be a guest on tonight's edition of CBS' "Late Show With David Letterman." Obama will be Letterman's only guest on tonight's show. He has been on the show before, but not since he became President of the United States. Obama's Letterman visit will mark his second late night talk show appearance since he took office. In March, he visited NBC's "The Tonight Show With Jay Leno." The visit made him the first sitting president to appear on a late night talk show.