Alan Cumming dares do all in 'Macbeth' on Broadway
The actor tackles 15 roles from the Shakespearean tragedy along with a mental patient in a story that frames the performance. He finds it 'terrifying' but relishes the chance to try something that's never been tried before.NEW YORK — Like world-class athletes, actors often measure their achievements by the degree of difficulty. Does a part require an unusual amount of range? An extraordinary number of man hours…