Particularly maps which use publicly available information to show you which of your neighbors contributed to whom: FundRace 2004 Block Party.
Some people will undoubtedly be a little unnerved by what can be visualized using disparate sources of data. Particularly since you can retrieve all contributors in a given ZIP Code, e.g. 95403.
What FundRace *ought* to do is provide an API interface to the data (which evidently they've spent more than a little effort to clean up enough to put into a database), allowing others to write applications which build on their efforts.
There's value in data sets.