The tensions between life and art, and between experience and imagination, lie at the heart of the 2003 chamber musical A Man of No Importance. When it premiered, Roger Rees played the homosexual director of a Dublin theater company in the 1960s, suffering from period repression and bigotry. Classic Stage Company’s revival stars Jim Parsons, the Big Bang Theory actor who apparently wants to demonstrate his acting and singing abilities beyond his Sheldon character—and succeeds.