Campaign Finance and Government Transparency
The post Citizens United world means far fewer limits on campaign spending, and far more unaccountable expenditures. But, there are ways to track much of it:
Sunlight Foundation has all sorts of government transparency projects. Check the reporting link for campaign finance information.
OpenSecrets has campaign finance data which is searchable by campaign, locale, donor, and more. Very user friendly, and there's an app too.
FEC -- the official Federal Election Commission site has campaign finance disclosures - regularly updated.
The California Fair Political Practices Commission has disclosure of who is funding our state ballot measures.
The National Institute on Money in State Politics has a followthemoney page where you can search by your district, by lobbyist, and arrange the data in many different ways.
Sunlight Foundation does a great job of making as much transparent as possible.
The Freedom of Information Act grants us access to all sorts of government information. Make a request, look for data, or study up on FOIA here.