Peep is a tool that allows you to listen to the health of your network. Rather than the obvious beeps and burps, it does this by producing a dynamic ambient soundtrack, which varies with the activity of various services. The theory is that the brain is a lot more sensitive to changes in ambient sound, and it doesn't require active concentration for you to take notice.
The ambient sound part of this is also available in two other bits of software: Boodler for Linux, and Aire Freshener for Windows. Aire Freshener comes with a whole bunch of nifty soundscapes (Star Trek Bridge? (TOS or TNG), Womb, Busy Resaurant, etc...).