Measure the distance from your current location to a fixed point using Google maps API V3
I'm running this in a simple node.js server but any http server will do. The simple node server i'm using can be goten from here : https://github.com/andrewpthorp/simple-http-server. All you have to do is use command line to browse to your local directory root and type nserver.
You can view the demo here : https://www.youtube.com/watch?v=9V6emGb0u2A