MATLAB-style plotting and graphing for Python. Also includes some of the "image" functions like imread and imshow, as well as support for the MATLAB figure, subplot, and charts like: bar, pie, plot, hist, polar, quiver, scatter, contour ... etc.
The Sandcastle Wiki. Sandcastle is the official Microsoft MSDN documentation generator (it reflects on assemblies and includes XML comments if they're available). Like NDoc ...
Sandcastle is the official Microsoft MSDN documentation generator. It's like NDoc, except Sandcastle can reflect over the source assemblies and works even when there are no XML documentation comments.
Great instructions on how to install various tools you would want for doing development with Visual Studio, Subversion and WiX. Particularly note the macro for generating GUIDs!
Libertà is an open source suite of portable software and wrappers for making existing software portable, including a custom launcher, backup tools and more.
A .NET control to do collapsible control panels like Explorer has in "Open" view, which properly supports windows themes (with source code and everything).