PAT BENATAR AND THE HIGH SCHOOL CHOIR: Students from the Lindenhurst High School Choir will perform along with rock singer Pat Benatar, Thursday at 12:30 p.m., to help kick off the summer season at Union Square Park. The program includes “Let the Sun Shine In,” “Here Comes the Sun” and other songs. Free. 14th Street between Broadway and Park Avenue South; (212) 485-6800.