You can control whether sounds and background music are played by checking the appropriate options in the Options menu.

If you’ve heard the background music, you’re probably wondering what the hell it is.  It is computer-generated music; the pitch, duration, and length of each note are determined on the fly by a semi-random process known as “1/f”.  Anyone interested in a general-level introduction to 1/f music and other naturally-occurring 1/f processes should check out chapter 1 of Martin Gardner’s book, Fractal Music, Hypercards, and More...  There is a bibliography at the end of the chapter which gives more technical references.

The background music is off by default, for obvious reasons.