freshmeat maintains the Web's largest index of Unix and cross-platform software, themes and Palm OS software. Thousands of applications, released under an open source license, are meticulously cataloged in the freshmeat database, and links to new applications are added daily.
The freshmeat API deals with data gathering and data entry across a number of data types including projects, comments and screenshots. The API uses RESTful calls and responses are formatted in XML and JSON.
If you're reading this, I probably don't have to tell you about Freshmeat. This repository of open source code and projects has been around quite a while, and is used by a number of prominent projects. What you may not know, however, is that Freshmeat offers a well-designed Freshmeat API to help developers access the data on Freshmeat for any purpose that makes sense.