An Open Source media-tagging library with support for ID3, ASF, APE, Xiph, and other media tags embedded in everything from .asf to .wv including mp3 and mpeg4, wmv, etc.
Supports a large variety of movie and music formats and abstracts away the differences so you can just write: file.Tag.Title, file.Tag.Duration ... etc.
OpenTF is an open source (BSD licensed) implementation of the Team Foundation assemblies and TF client which may actually be better than the base TF PowerTool
The Tao Framework for .NET is a collection of bindings to facilitate cross-platform media application development utilizing the .NET and Mono platforms. Lots of library wrappers: OpenGl FreeGlut OpenAl Cg Lua Sdl PhysFs Glfw FFmpeg FreeType ... etc
reacTIVision is an open source, cross-platform computer vision framework for the fast and robust tracking of fiducial markers attached onto physical objects, as well as for multi-touch finger tracking.
RRDtool is the OpenSource industry standard, high performance data logging and graphing system for time series data ... has interfaces in all the usual open source scripting languages
Micro pledge ... a system for putting pledges or bounties on code features that you'd like to see in your favorite software. Free for open source projects -- proprietary or closed-source projects have some fees associated with them (on the developer side).
The XML IDE ... modeling, editing, transforming, and debugging XML-related technologies, including an awesome graphical schema designer, code generation tools, file converters, debuggers, profilers, database integration, and explicit support for XSLT, XPath, XQuery, WSDL, SOAP, and Office Open XML (OOXML) documents. It even included Visual Studio and Eclipse plug-ins...
PureMVC is a lightweight framework for creating applications based upon the classic Model, View and Controller concept.
Based upon proven design patterns, this free, open source framework which was originally implemented in the ActionScript 3 language for use with Adobe Flex, Flash and AIR, is now being ported to all major development platforms.