Very influential horror film, released in Germany in 1919. Directed by Robert Wiene. Starred Werner Krauss as the sinister Dr. Caligari and Conrad Veidt as Cesare the Somnambulist. An excellent example of both the silent film and German expressionism, the movie follows the evil exploits of Dr. Caligari as he sends Cesare, a sideshow dupe who has been kept in a trance for years, on a number of murderous rampages. He is, of course, opposed by noble young heroes who wear too much eye makeup (modern goths have no idea how much they owe to German expressionism). The film ends with a twist that grates on modern sensibilities, but was probably state-of-the-art when it was filmed.

If you're a film buff or a horror fan, you should consider this to be required viewing; German expressionism had a major impact on both the language of cinema and how we tell horror stories. The cinematography is also a treat--the surreal, dreamlike lighting and set design are as much a part of the story as the plot or the characters.