SWINGING FOR THE CAUSE: It will be Rat Pack-and-Showgirl time on Saturday, Feb. 21, when the Manhattan Society sponsors the 17th annual Casino Night Benefit for the National Multiple Sclerosis Society. This year’s theme is "Vintage Vegas," which should be a good fit for the evening’s musical stars, the Steve Marshall Band, known in many circles as New York’s "Ultimate Party Band." Marshall and company will be playing into the night for upwards of 1000 guests at the Marriott Marquis Times Square. For ticket info 212