Looking for something to do on a Saturday night that features exciting contemporary arts in a fun festival atmosphere? Then mark your calendars for September 26, when Art All Night: Nuit Blanche DC returns for the fifth year! From 7:00 pm to 3:00 am, the neighborhoods of Congress Heights, Dupont Circle, H Street NE, North Capitol and Shaw will present an eclectic mix of visual arts, performance, music and activities. And it’s all free…