Start the New Year with an afternoon of chamber music, in a familiar Park Slope gathering place. Cellist Benjamin Larsen and pianist Hyungjin Choi—longtime musical partners on and off the concert stage—offer a richly varied program that opens with Bach’s radiant Sonata written for viola da gamba, followed by 20th-century Bohuslav Martinů’s Cello Sonata No. 1 that is both lyrical and rhythmically charged. After intermission, you’ll hear a short, rarely performed musical portrait by Virgil Thomson, leading into Mendelssohn’s exuberant Second Cello Sonata. St. John’s Church, 139 St. Johns Place just off Seventh Avenue. Subway: Q, 2, 3. Bus B41, B67, B69.