Getting some types of public data is easy. For patent data, you can go to the patent office's website or any number of third-party sites. Information about pending legislation is available from Congress or various private alternatives.
But getting documents from the Internal Revenue Service is a lot more complicated. All tax-exempt organizations file a form 990, which provides the public with basic information about organizations' leadership and financial health. In theory, these are public documents available to anyone. In practice, getting a copy of an organization's 990 filing is a huge headache, as this funny flowchart form OpenSecrets.org shows.
There's no reason for things to work like this. Many organizations already e-file their 990s. There's no reason the IRS couldn't convert those filings to PDFs and put them directly on their websites. Instead, the IRS converts these (as well as paper forms) to unsearchable TIFF files, burns them on a DVD, and sells them for hundreds of dollars per year. It's a crazy, antiquated system, and it drives open government advocates crazy.
Many 990s are available from the non-profit rating website Guidestar and the Economic Research Institute. But it would be even better if the full database of 990 data were freely available from the IRS.
Read my in-depth take on the IRS's problem with 990s here.