Reflector is a class browser, analyzer and documentation viewer. Reflector allows to easily view, navigate, search, decompile and analyze .NET assemblies in C#, Visual Basic and IL.
Download here. Presentation here.
Resourcer is an editor for .resources and .resx files used with the .NET platform. Resourcer allows editing of strings, import of bitmaps and merging of resources from different sources.
Download here. Source here.
Writer is a simple editor for HTML files. Writer supports text layout and formatting, hyperlink editing and insertion of dates and pictures.
A Silverlight graphics demo in XAML and C# with MP3 audio.
Start here. Source here.