WOLF TRAP OPERA COMPANY -- "Sweeney Todd: The Demon Barber of Fleet Street," Friday at 8 and Sunday at 2. "The Latest Word," recital program, Saturday at 8. The Barns of Wolf Trap, 1635 Trap Rd., Vienna. 703-218-6500 or 703-938-2404.
OPERA BEL CANTO -- Donizetti's "Mary Stuart," Sunday at 2. Mount Vernon Place United Methodist Church, 900 Massachusetts Ave. NW. 202-393-5323.
BEL CANTANTI -- Rachmaninoff's "Aleko" and other works, Sunday at 7:30. Christ Lutheran Church, 8011 Old Georgetown Rd., Bethesda. 301-652-5160.
AIR FORCE BAND ensembles, Friday at noon. Free. National Air and Space Museum Udvar-Hazy Center, 14390 Air & Space Museum Pkwy., Chantilly. 202-767-5658.
CHESAPEAKE ORCHESTRA -- Friday at 7, conducted by Jeffrey Silberschlag in Beethoven's Piano Concerto No. 5 and Bruckner's Symphony No. 4. Free. St. Mary's College of Maryland, Route 5, St. Mary's City, Md. 240-895-2024.
CITY OF FAIRFAX CONCERT BAND -- Friday at 7:30. Free. Lake Accotink Park, 7500 Accotink Park Rd., Springfield. 703-425-9300 or 703-324-7469.
BALTIMORE SYMPHONY ORCHESTRA -- Friday and Saturday at 7:30, in a pops program with singer Johnny Mathis. Joseph Meyerhoff Symphony Hall, 1212 Cathedral St., Baltimore. 800-442-1198.
ARMY BAND ensembles, Friday and Tuesday at 8. Free. West Terrace of the U.S. Capitol. 703-696-3399 or 202-619-7222.
NATIONAL SYMPHONY ORCHESTRA -- Friday at 8:15, conducted by Leonard Slatkin with the Choral Arts Society of Washington in Barber's Adagio, Bernstein's "Symphonic Dances" from "West Side Story" and Gershwin's "Porgy & Bess" (excerpts). Saturday at 8:15, conducted by Leonard Slatkin with pianists Musa Rubackyte in Mendelssohn's "A Midsummer Night's Dream," Liszt's Piano Concerto No. 1 and Mahler's Symphony No. 1. Filene Center, Wolf Trap Park, 1551 Trap Rd., Vienna. 703-218-6500 or 703-255-1860.
NATIONAL ORCHESTRAL INSTITUTE Orchestra, Saturday at 8, conducted by David Robertson in Sibelius's "En Saga," Boulez's "Notations" and Stravinsky's "Petrouchka." Dekelboum Concert Hall, Clarice Smith Performing Arts Center, University of Maryland, Route 193 and Stadium Drive, College Park. 301-405-2787.
229TH ARMY NATIONAL GUARD Band -- Sunday at 4. Free. Harborplace Amphitheater, Pratt and Light streets, Baltimore. 800-427-2671 or 410-332-4191.
NAVY BAND ensembles, Monday and Thursday at 8. Free. West Terrace of the U.S. Capitol. 202-433-2525 or 202-619-7222.
NAVY BAND -- Tuesday at 8. Free. Navy Memorial, 701 Pennsylvania Ave. NW. 202-433-2525.
AIR FORCE BAND ensembles, Wednesday at noon. Free. National Air and Space Museum, Seventh Street and Independence Avenue SW. 202-767-5658 or 202-633-1000.
MARINE BAND ensembles, Wednesday at 8. Free. West Terrace of the U.S. Capitol. 202-433-4011 or 202-619-7222.
U. OF MARYLAND COMMUNITY Band, Thursday at 6:30. Free. Lion-Tiger Hill, National Zoo, 3001 Connecticut Ave. NW. 202-633-4480.
MARINE BAND -- Thursday at 7. Free. U.S. Marine Corps War Memorial, on U.S. 50 adjacent to Arlington National Cemetery, Arlington. 202-433-4011.
CITY OF FAIRFAX BAND -- Thursday at 8. Free. Veterans Amphitheater, Fairfax City Hall, 10455 Armstrong St., Fairfax. 703-385-7858 or 703-757-0220.
BELMONT BRASS & FRIENDS -- Friday at 7:30. St. Joseph's On Capitol Hill, 313 Second St. NE. 202-547-1223.
COURT DANCERS & RENAISSONICS -- Friday at 7:30. St. Mark's Episcopal Church, Third and A streets SE. 703-684-2114.
ARMONIA NOVA -- Saturday at 7:30. St. Mark's Episcopal Church, Third and A streets SE. 703-684-2114.
WASHINGTON METROPOLITAN Philharmonic ensembles, Sunday at 3. Free. The Lyceum, 201 S. Washington St., Alexandria. 703-799-8229 or 703-838-4994.
DREW MINTER & TREFOIL -- Sunday at 3. St. Mark's Episcopal Church, Third and A streets SE. 703-684-2114.
ENSEMBLE DA CAMERA of Washington -- Sunday at 6. Free. The Lyceum, 201 S. Washington St., Alexandria. 703-838-4994.
"GRACE CHURCH BACH FESTIVAL" -- Wednesday at 7:30. Grace Church, 1041 Wisconsin Ave. NW. 202-333-7100.
HESPERUS -- Thursday at 7:30, "Celtic Tiger: Ancient Irish Roots and Medieval Echoes," with Billy McComiskey, Zan McLeod and Robert Spates; gourmet reception at 6:30. Clarendon Ballroom, 3185 Wilson Blvd., Arlington. 703-525-7550.
JEONG-YOON CHOI -- pianist, Friday at noon. Free. Arts Club of Washington, 2017 I St. NW. 202-331-7282.
BABER & WEAVER -- Friday at noon. St. Mark's Episcopal Church, Third and A streets SE. 703-684-2114.
HOLLINSHEAD/BASS DUO -- Saturday at 4. St. Mark's Episcopal Church, Third and A streets SE. 703-684-2114.
EDWARD NASSOR -- carillonneur, Saturday at 6. 2 Free. Netherlands Carillon, Fort Myer and Marshall drives, Arlington. 703-289-2500.
JUSTUS PARROTTA -- organist, Sunday at 6. Free. National Shrine of the Immaculate Conception, 400 Michigan Ave. NE. 202-526-8300.
DENNIS SOBIN -- guitarist, Monday at noon. Free. The Old Post Office Pavilion, 1100 Pennsylvania Ave. NW. 202-289-4224.
JOAN McFARLAND -- soprano, mezzo-soprano Gail Collins, cellist Fred Lieder and pianist Stephen Brown, Tuesday at 12:10. Free. Church of the Epiphany, 1317 G St. NW. 202-347-2635.
CHORALIS -- Friday at 8, Bach's "Magnificat" and Mozart's "Requiem." Falls Church (Episcopal), 115 E. Fairfax St., Falls Church. 703-237-2499.
NORTH AMERICAN WELSH CHOIR -- Saturday at 7:30. Church of the Epiphany, 1317 G St. NW. 202-357-3030.
NAVY SEA CHANTERS -- Sunday at 6. Downs Park, 8311 John Downs Loop, Pasadena. 410-222-6230.
NATIONAL GALLERY VOCAL Arts Ensemble, Sunday at 6:30. Free. West Garden Court, National Gallery of Art, Sixth and Constitution NW. 202-842-6941.
ALBAN CHORALE -- Sunday at 7:30. Free. Newton W. Edwards Amphitheater, Mason District Park, 6621 Columbia Pike, Annandale. 703-941-1730.
"WASHINGTON SUMMER SINGS" -- Tuesday at 7:30, Bach's "B Minor Mass," conducted by Robert Shafer. Sponsored by the New Dominion Chorale at Western Presbyterian Church, 2401 Virginia Ave. NW. 703-442-9404.
SLAVIC MALE CHORUS OF Washington -- Thursday at 7:30. Free. Nottoway Park, 9601 Courthouse Rd., Vienna. 703-938-7532 or 703-324-7469.