"NBC Experiment in Television" The Cube (1969)

http://www.imdb.com/title/tt0291118/

The Cube was an hour long teleplay that aired on NBC's weekly anthology television show NBC Experiment in Television on February 23, 1969. The production was produced and directed by puppeteer Jim Henson, and was one of several experiments with the live-action film medium which he conducted in the 1960s, before focusing entirely on the Muppets and other puppet works. The screenplay was co-written by long-time Muppet writer Jerry Juhl (who also appears in a cameo).

The teleplay starred Richard Schaal as a man trapped in a cubical white room that anyone else could enter and leave, but which he himself apparently could not leave. The main character, simply named "The Man," is subjected to an increasingly puzzling and frustrating series of encounters as a variety of people come through various hidden doors. But as many remind him, he can only leave through his own door, so he must find it.

 Richard Schaal ...  The Man in the Cube 
 Hugh Webster ...  Arnie 
 Rex Sevenoaks ...  Manager 
 Jack Van Evera ...  Prisoner 
 Jon Granic ...  Straight Man / Sergeant 
 Guy Sanvido ...  Comic Fritz 
 Eliza Creighton ...  Seductress 
 Don Crawford ...  Black Militant 
 William Osler ...  Scientist 
 Jerry Nelson ...  Monk 
 Sandra Scott ...  Decorator 
 Claude Rae ...  Dr. Conners 
 Don McGill ...  Professor 
 Ralph Endersby ...  Guitarist 
 Trudy Young ...  Liza #1 

The teleplay only aired twice (it was rerun in 1970).

The central plot point is strikingly similar to "The Squirrel Cage", a short story by Thomas M. Disch that was published in 1967. Both stories are about a man who is imprisoned in a big white cube. The man doesn't know why he's there and never finds out. He never gets out of the cube. Disch's story also appeared in his collection Fun With Your New Head (Doubleday, 1968).

In 2007, the German Fringe Theater troupe glassbooth, directed by Roger Hoffmann and starring Jens Dornheim presented a live stage adaptation of The Cube titled KUBUS.  A promotional short film is also included.