Create an Isochrone Map
Isochrone maps show travel times from a given location. Most isochrone Google Maps allow the user to select a location and then see how far they can travel in a set time from that destination.
One of the best isochrone maps built with the Google Maps API is the
London at Night map.
The London at Night map shows how long it takes to get to anywhere in London by night bus.
If you would like to create your own isochrone map then a good place to start is the Flying Memes tutorial. The Flying Memes isochrone map uses the directions service to search for points that surpass a given time limit from the given location.