A final exam had just one question: ‘Write the best possible final exam question for this course, then answer it.’

One student immediately wrote, ‘The best possible final exam question for this course is “Write the best possible final exam question for this course, then answer it.”‘

— Jan Harold Brunvand, Too Good to Be True: The Colossal Book of Urban Legends, 2011

(Presumably the answer was “Write the best possible final exam question for this course, then answer it.”)