Gravity Monkey has a cool project called GPS Chimes, a Mologogo based construction that triggers Chimes based on GPS data.

GPS Chimes (Gravity Monkey)

My GPS Chimes are wind chimes that are triggered by an individual’s proximity to a given location — networked via GPS, cellphone and the internet. Think of it as mile-wide radius around the wind chimes, where my networked presence and GPS location (via Mologogo) send a virtual breeze to announce my travel home.

Honey, I’m home!
– I know darling, heard you coming from a mile away!

Source code and images of the construction can be found on Gravity Monkey.