The purpose of the "musical bench" is to play music or other pre-recorded audio when two people are sitting on the bench and touch in some way or another - whether it be by finger, hand or other skin. It's a fun idea that could be used at parties or other events as another amusement.
The theory behind it is quite simple - the two people close a very low-current circuit, and the change in current is detected by the Arduino which then triggers audio playback via an MP3 shield. You can see this in action through the following video:
This is also a neat demonstration of using the human body as another form of input, so for complete details visit the project Instructable page. And for more, we're on facebook, Google+, and twitter - so follow us for news and product updates as well.