"OpenSecrets.org is your nonpartisan guide to money's influence on U.S. elections and public policy."
A fellow real estate enthusiast posted a link on twitter to a very interesting site: OpenSecrets.org: Money in Politics. Already, I've learned that the 22601 (Winchester City) zip code gives around two times as much as the average zip code.
Have fun checking out the site and get results by map or by list. You may find out a lot about your neighbors!