Movie: Monty Python and the Holy Grail (1975)
Writer: Graham Chapman, Terry Gilliam, John Cleese, Eric Idle, Terry Jones, and Michael Palin

Having lost none of its satirical hilarity, the intentionally outlandish Monty Python and the Holy Grail (written, directed, and acted out by the infamous British comedy troupe) never fails to impress with its intelligence and sneaky surprises. At first, the film presents itself as a spoofy account of the King Arthur and his Knights of the Round Table, but an out-of-nowhere cutaway sequence shows a present-day historian being killed by a knight while relaying Arthur's legend on camera.

There are several like-minded clues throughout Holy Grail, but it's not until the closing seconds that the Monty Python gents' shrewd little twist reveals itself: Who we've thought to be Arthur, his men, and their enemies are all just escapees from a loony bin. The paddy wagon and cops that interrupt the wannabe knights' impending battle make this unanticipated fact abundantly clear.