An annual tradition! On Oct. 20, 2 and 4 p.m., the Kennedy Center Concert Hall transforms into a ghostly sight when their ghoulishly attired musicians perform new and old classics to celebrate Halloween. Arrive early for trick-or-treating and a special Haunted Hall Musical Instrument “Petting Zoo.” Most enjoyed by age five, up. All patrons, regardless of age, must have a ticket. $15 to $18. kennedy-center.org.