A truly remarkable range of resources from the U.S. Federal Government, that is made all the more interesting by Data.gov Next Generation:
Data.gov starts an exciting new chapter in its evolution to make government data more accessible and usable than ever before. The data catalog website that broke new grounds just two years ago, is once again redefining the Open Data experience. Learn more about Data.gov’s transformation into a cloud-based Open Data platform for citizens, developers and government agencies in this 4-minute introductory video.
Developers should take a look at: http://dev.socrata.com/.