I've finally seen all of THE CUBE in its entirety, and I have to say that this thing is really incredible. I mean, it is so ahead of it's time: it's only 1969, but this is the kind of thing that wasn't the norm on network television until a couple of years later when ALL IN THE FAMILY paved the way for edgier TV (oh, and don't show this to people who aren't avid followers of Jim Henson, they'll probably fall into a coma when they hear swearing in a Henson production).
It's really disturbing too, but not in a bad way, in a good way: you really feel what The Man In The Cube feels, you feel just as frustrated and confused as he does by all of these strange and bizarre people who keep just walking in on him, and walking out just as quickly and mysteriously, and just as much as he wants to get out of the Cube, that's how much you want him to get out.
I also really enjoyed the on-screen cameos made by both Jerry Juhl and Jerry Nelson.