The University of Washington Campus Map is a great example of how the Google Maps API can be used to create a guide to a university campus.

I really like the building overlay on the map. Just the simple addition of shadows to the building outlines gives the map a nice sense of depth. Another really useful feature is a white circle outline that snaps to the interactive buildings on the map. As you mouse-over the map the white circle snaps to the nearest building. This simple feature greatly adds to the usability of the map, as it guides the user to the interactive elements on the map.

The map also includes all the usual features you would associate with a campus map. You can search for individual buildings and you can overlay useful locations, such as food, parking, libraries, computer labs etc.