BIG SAM'S FUNKY NATION: Presiding over his Funky Nation is Big Sam, formerly the trombonist for the Dirty Dozen Brass Band, who blows the funk out of his trombone and refuses to let the audience sit still. Between solos and trombone riffs, Big Sam second-lines (a uniquely New Orleans style of street-dance) and gets the crowd going both in movement and in replies to his call-and-response MC-style. A talented group of jazz-trained musicians makes up the Funky Nation