Browser Mute

So, how often have you been in your own little world, headphones clamped around your head pumping out some fine tunes via iTunes WHY and surfed onto some web page with some god awful sound effects loop or worse a page with content you actually want to read but some multimedia ad keeps asserting itself with some annoying chirp?

It happens to me all the time and leads me to this one question. Where is the 'mute' button on my browser?