'One Flew Over the Cuckoo's Nest'
(1975)
Starring: Jack Nicholson, Louise Fletcher, Danny DeVito, Brad Dourif, Christopher Lloyd

The granddaddy of all lunatic movies, One Flew is based on the Ken Kesey novel of the same name. It's no comedy, but you will laugh. It tells the tale of McMurphy (Nicholson), a crazy con man institutionalized against his will who sets out to prove he can never be tamed.