The social hub of Main Street on any given Friday or Saturday night is the sidewalk outside the Strand, where theatergoers gather underneath the bright vertical marquee that’s kind of a totem of Rockland’s downtown. Restored in 2004, the nearly century-old theater hosts first-run indie movies and documentaries, concerts by national touring bands like BeauSoleil and Patty Griffin (the schedule is Americana-heavy), and the occasional local theater performance.