The Rally .NET SDK by Joshua Stupplebeen interacts with the API, even though Rally Software does not maintain the kit actively. User guide provides links to access REST API and Web Services documentation. For support, ask a question at http://stackoverflow.com/questions/ask?tags=rally
The National Institue of Standards and Technology (NIST), has created created AppVet. AppVet is an open-source tool that IT groups can use to test applications for use on government networks. AppVet was designed to easily integrate with third party apps and tools (e.g. antivirus software, analyzers, vulnerability repositories, etc.) through simple APIs.