Having known Mr. Cage personally, I can tell you that his tongue was always firmly in his cheek.
http://www.nytimes.com/2006/05/05/arts/music/05cage.html?ex=1147060800&en=a827291ed8a1627a&ei=5087%0AI built the one and only 4'33" Music Box, now in the collection of a couple in Woodside, California. It's a miniature, plexiglass piano that you wind up, and then it plays...
nothing. However, it has an official-looking Reuge Music Box Company label on the bottom that reads, '"4'33," by John Cage.'"
Also, I saw Yvar Mischicoff (sp?) perform the work in 1982. He strode out to the piano, lifted the keyboard cover, and then sat there for four minutes and thirty-three seconds, playing not one single note. At the "end," he closed the cover, stood up, and walked off stage again.
There's a hologram recording of this "rendition," but I don't know where it is. Possibly, somewhere on the internet.
"4'33" is even available as published sheet music, in case you want three pages of rests in every single bar (!).
It's very... umm... restful.
[attachment deleted by admin]