This weekend, the American Mavericks festival continues with programs featuring three of the most distinctive vocalists today. On March 10 and 14, Jessye Norman, Meredith Monk, and Joan La Barbara participate in an American Mavericks performance of John Cage’s Song Books led by MTT. The American pianist Jeremy Denk performs Cowell’s percussive yet melodic Piano Concerto in three movements, entitled “Polyharmony,” “Tone Cluster” and “Counter Rhythm.”