In 1952, composer John Cage came up with something he called “4’33″” (read as “four thirty-three,” as in four minutes and 33 seconds). Divided into three movements (30 seconds, 2:23 and 1:40), it involves the musician (or musicians) to sit at their instruments for exactly 4:33 and play…nothing. They just sit there. Cage meant for the experience to get people to hear the sounds of the environment around them. What did a full concert hall sound like when there was nothing being played? Avant garde people looked the existentialism of it all while everyone thought it was a little bent, if not a little insane. No wonder “4’33″” became Cage’s most controversial, er, composition. But here’s where it gets really dumb. You can get “4’33” on iTunes. And it’s only 99 cents. And yes, you also get the 90 second preview.