The Cube is a 1969 hour-long teleplay that aired on NBC's weekly anthology television show NBC Experiment in Television. The production was produced and directed by puppeteer and filmmaker 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.
The teleplay only aired twice: first on February 23 of 1969, with a rerun in 1970.
A unnamed man, simply called "The Man" (Richard Schaal) is trapped in a cubical white room where anyone else can enter and leave, but which he himself apparently can not leave. The main character, 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 to leave.
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.