"Miracle Cure" by The Who is 14 seconds... and one of my friends, who listens to the darker, goth type stuff, told me that Marilyn Manson (or maybe it was Alice Cooper, I can't remember ) did an album with like 99 songs, the first 97 being each 2 seconds long or something, and they were all silent. I don't know if that really constitutes as a song though!