It is the 100th birthday of composer John Cage (1912), who might have perpetrated the greatest hoax on the music world with his best known work, 4'33" (1952), except that he was perfectly serious. For four minutes and 33 seconds, the orchestra sits silently, playing nothing. What the audience experiences is the sounds of the environment—people rustling, coughing, breathing. (Here's a recording of a performance by the BBC Orchestra.)
When he was in high school in 1928, Cage gave a speech in which he suggested a national day of silence. "By being hushed and silent," he said, "we should have the opportunity to hear what other people think." (In this election season, what a marvelous thought!)
Though his consideration of silence as music came to him early, he may have been spurred to act on his idea after reading the I Ching, the Chinese classic text that helps identify order in chance events. Also, Cage is said to have viewed a series of paintings by his friend Robert Rauschenberg called White Paintings in 1951. They were four canvases covered with white house paint. Cage thought they were like looking at silence. In different light they appeared differently. Shadows and dust changed them, too. Cage seems to have translated the idea to his own medium.