The Federal Register is touted as "The Daily Journal Of The United States Government". Its website, federalregister.gov, allows access to the documents published there, which include proposed rules, final rules, public notices, and Presidential actions. It's a pretty interesting and useful look into what the US Government is doing, and how it might affect your life. Amazingly enough, it has a truly open source project, the full-featured Federal Register API to allow access to the Federal Register within applications.
The print-based, official edition of the Federal Register displays information in a dense format that makes it difficult to read and process documents in meaningful and innovative ways. We built this unofficial, XML-based edition of the Federal Register to overcome the technical limitations of the official edition and to demonstrate how a new version can more effectively convey regulatory information to the public. In the future, this site will be presented to the Administrative Committee of the Federal Register for their determination as to whether it should be granted official status under 1 CFR 5.10.
The API is fully RESTful, formatting responses in JSON and JSONP. There is a Ruby gem for the API available on the site's Github, along with the full source of the site, the API, and some other fun things. All in all, it seems well designed, and everything is free to use as you'd expect.
Access to this information isn't the easiest or most convenient, so there's a lot of room for cool apps using this API. Political news sites could integrate it, or simply use it to access press releases, for example. One could make clients for mobile devices, to format these articles for easy reading on iPhone or Android. Adding this as a Feed to news aggregation programs, or perhaps even simply regurgitating it into useful RSS feeds, could be a real help for the average person who simply wants to know a little more about what's going on in the government. I hope to see some really interesting apps come out of this that will help all of us become more informed.