My wife and I saw this on a lark and were, as everyone above, more than pleasently surprised, it was just the right level of juvenile, paradoy and for me, most importantly it was just the right degree of self-aware.. sometimes it threw it at you such as when Cube is talking about where they got the idea for the program, or (slightly) more subtle such as during the car chase.
Oh, and the end.. Jesus.. the ending.. we were crying.