Spencer Tracy and Katharine Hepburn star as wealthy Californians who consider themselves progressive -- until their daughter brings home her black fiancé, Sidney Poitier. Produced in 1967, Guess Who's Coming to Dinner took on pointed subject matter (for its time). Watching Tracy's and Hepburn's characters struggle with prejudices they didn't know they had is a powerful metaphor for a society's long-overdue awakening.