Try this: mute your computer speakers for a second. Sit perfectly still. Don't make a sound. Is it totally silent where you are? I'm guessing not. In fact, I'm certain not. As far as anyone knows, it's impossible for someone who can hear to ever experience actual silence. Even in an anechoic chamber - a room scientifically designed for silence - you just end up listening to the sound of your own blood pumping.
Still, it's pretty rare for things to get even that quiet in every day life (in fact, being in an anechoic chamber is so disorienting that the longest anyone has ever lasted in one is forty five minutes!). Chances are that, while you read this, you can hear traffic, wind, the buzz of your computer's fan, and any number of other sounds. So not silent, exactly, but if you actually stop for a second and get as quiet as possible, whole new worlds of tiny sounds start to reveal themselves to you. Try it some time!
Some musicians over the years have explored the idea of silence. The most famous of these experiment is John Cage's 4'33". It's a piece of "music" that involves no music at all. The performer sits in silence for four minutes and thirty three seconds, and then the 'piece' is over. It challenges our very definition of music, but one thing is for certain - listenong to 'silence' for four and a half minutes can, under the right circumstances, be a profound experience.
Plus, it's probably the most famous piece of music that you can perform by yourself, anywhere, any time. So next time you're at a party and some dude pulls out an acoustic guitar, counter with an impromptu performance of 4'33" and just see what happens.