Google recently released several open source projects:

• RatProxy: a passive web application security assessment tool
• Protocol Buffers: a way of encoding structured data in an efficient yet extensible format and the format used for almost all of Google's internal RPC protocols and file formats.
• GoogleTest: a framework for writing C++ tests on a variety of platforms (Linux, Mac OS X, Windows, Windows CE, and Symbian).

Interesting for developers to check out!