Neighboroo is an interesting too in which it maps such statistics as 'political affiliation', 'air quality', and 'crime' across the United States.  You can zoom and scroll to specific locations or just view the entire map to just get an overview.  Check it out.

Previously:
Hack Google Maps, Google Moon, zipdecode, Gallery and google maps meet, Google Maps and WiFi used for traffic court evidence, Another cool google maps hack