Opera
Dell’Arte Opera (Friday through Sunday) This ensemble, a valuable source of performing experience for young artists, is staging two operas set in ancient Rome this summer. Monteverdi’s “Incoronazione di Poppea” (Friday and Sunday) is directed by Victoria Crutchfield. Christopher Fecteau conducts Mozart’s “Clemenza di Tito” (Saturday); the director is Walker Lewis. Friday and Saturday at 8 p.m., Sunday at 3 p.m., East 13th Street Theater, 136 East 13th Street, Manhattan, (646) 796-3492, dellarteopera.org; $30, $20 for students and 65+. (Zachary Woolfe)
★ Glimmerglass (Friday and Saturday) It is always worth the drive to Cooperstown, N.Y., to attend this summer festival. Productions are presented in an ideal opera house, seating just 900, amid beautiful rural environs. Steve Smith wrote in The New York Times that the festival “rises to new levels of innovation, curiosity and, yes, chutzpah.” In this final weekend of the festival, all but one of the four major productions, “Passions,” can be seen. Wagner’s “Flying Dutchman” (in German with projected English text) is directed by the festival’s general and artistic director, Francesca Zambello, and features Ryan McKinny as the Dutchman and Melody Moore as Senta. The classic Lerner & Loewe musical “Camelot,” presented with a full orchestra and without amplification, is directed by Robert Longbottom, with Nathan Gunn as Lancelot and David Pittsinger as King Arthur. Verdi’s “King for a Day,” the composer’s second opera, a rarely-heard comedy, is being presented in a new English adaptation, directed by Christian Räth and conducted by Joseph Colaneri. “Camelot”: Friday at 7:30 p.m.; “King for a Day”: Saturday at 1:30 p.m.; “The Flying Dutchman”: Saturday at 8 p.m. Glimmerglass Opera, 7300 State Highway 80, eight miles north of Cooperstown, N.Y., (607) 547-2255,  glimmerglass.org; $26 to $132; $10 to $25 for youth (18 and younger). (Anthony Tommasini)
Classical Music
Bargemusic (Friday through Sunday, Wednesday) The weekend at this floating concert hall brings classics: on Friday, Schubert and Liszt from the pianist Gleb Ivanov; on Saturday, music for shifting configurations of piano, violin, viola and clarinet; and on Sunday, the final three of Bach’s six suites for solo cello, with Jeffrey Solow. An abrupt shift on Wednesday brings the first of four performances in the Here and Now series’ Labor Day festival, featuring a motley assortment of works by Elliott Carter, George Perle, Russell Platt, Patrice Fouillaud, Colin Jacobsen, David Del Tredici, Oliver Knussen, Thomas Adès and others. At 8 p.m., except for Sunday when the performance starts at 2 p.m., Bargemusic, Fulton Ferry Landing, next to the Brooklyn Bridge, Brooklyn, (800) 838-3006, bargemusic.org; $35, $30 for 65+, $15 for students. (Woolfe)
Taka Kigawa (Monday) This excellent, adventurous pianist has become a classical mainstay at Le Poisson Rouge, drawing large crowds with his performances of Bach and contemporary fare. Here, he focuses on 20th- and 21st-century works, offering Elliott Carter’s Piano Sonata and “Night Fantasies”; John Zorn’s “Carny”; and the Preludes by Sean Shepherd, a rising young American composer. At 7:30 p.m., Le Poisson Rouge, 158 Bleecker Street, near Thompson Street, Greenwich Village, (212) 505-3474,lepoissonrouge.com; $20 in advance, $25 at the door. (Vivien Schweitzer)
Maverick Concerts (Saturday and Sunday) This season’s concerts, which take place in an atmospheric barn built in 1916, celebrate the Britten centenary. Saturday’s program, which explores the connection between Britten and Rostropovich, features the cellist Zuill Bailey and the pianist Robert Koenig in Britten’s Sonata in C (Op. 65), as well as works by Henry Eccles, Schubert and Lukas Foss. On Sunday the Enso String Quartet performs Britten’s String Quartet No. 2, Mozart’s Quartet in C “Dissonant” and Verdi’s String Quartet. Saturday at 6:30 p.m., Sunday at 4 p.m., Maverick Concert Hall, 120 Maverick Road, Woodstock, N.Y., (800) 595-4849, maverickconcerts.org; $25 and $40, $5 for students. (Schweitzer)
Mostly Mozart Festival (Friday and Saturday) After a focus on Beethoven and a new-music-hungry residency by the International Contemporary Ensemble, the festival closes with a not-just-mostly, but all-Mozart program. Louis Langrée conducts the festival orchestra in the last three symphonies, Nos. 39, 40 and 41 (“Jupiter”). At 8 p.m., Avery Fisher Hall, Lincoln Center, (212) 721.6500, lincolncenter.org, $25 to $85. (Corinna da Fonseca-Wollheim)
Tanglewood (Friday and Sunday) The closing weekend at the Boston Symphony Orchestra’s summer retreat in the Berkshires brings, on Friday, the orchestra’s assistant conductor, Andris Poga, in a program that includes Stravinsky’s Concerto for Piano and Winds (with Peter Serkin as the soloist) and Beethoven’s Seventh Symphony. And, for a traditional finale, more Beethoven: the mighty Ninth Symphony, conducted by Bernard Haitink with Erin Wall, Tamara Mumford, Joseph Kaiser and John Relyea as the soloists. Friday at 8:30 p.m., Sunday at 2:30 p.m., Koussevitzky Music Shed, Tanglewood Music Center, Lenox, (888) 266-1200, bso.org; $9 to $105. (Woolfe)