Why our stomaches growl when we're hungry...

How I Heard About This: I once went to see almost completely silent art-house film whilst studying directing at university. Halfway through I had to leave as my stomach was being so noisy, and almost everyone in the cinema couldn't stop laughing (including me). I ate something and was able to sneak back to watch the end. A friend of mine reminded me of this story today and I decided to try and find out how it happened.
Main Source: http://en.wikipedia.org/wiki/Borborygmus
Backup Source: http://answers.yahoo.com/question/index?qid=20081202151229AA5HGx8
Topic: Biology

This is actually called "borborygmi". This is the process where by the walls of your intestines squeeze together to mix and digest food as well as move food down the digestive tubes. The brain switches on and off the digestive processes throughout the day, so you may hear these sounds even when you're not hungry. We hear these sounds more clearly when we are hungry as there is no food in there to muffle the sounds.

Borborygmi - great word!