Sometimes you will visit a web site and suddenly your speakers will start spitting out sounds. I don't know about you, but the first thing that I do when this happens is curse silently. One of two things will happen at this point. I will find a button to turn off the sound and stay or I will surf to another site.
Every new webmaster seems to do it at least once.
Add background sound to their web site. And, you know, there are times when it is appropriate. A musicians site, for example, might be the right place. Or a site all about MIDI files might also have a background sound. I ran across a MIDI site once that played a random, different MIDI each time a page was loaded.