Bing has this new tech demo called Destination Maps, where you can pick a point on a map, choose a custom area, and they will render out a map with major roads on it. While that may not sound terribly interesting, it can adjust the style of the map on the fly. It does take a little time to generate the map, but it could be fun if you were putting together some sort of scavenger hunt or providing a custom map to an event.
Here are the “sketch” and “treasure map” styles:


You can try it for yourself here