I ♥ open source. Here are the projects I created and/or maintain.
DynamicImage is a high-performance image manipulation library for ASP.NET. This isn't really my project - it was created by Sound in Theory. In my own fork, I've been steadily moving it forwards, to the point where I think it's a great choice for ASP.NET image manipulation, especially if you need more complex layering or combination of filters.
Gemini is a WPF framework for creating IDE-like applications. It includes a number of modules that provide useful out-of-the-box functionality: CodeCompiler, CodeEditor, ErrorList, GraphEditor, Inspector, Inspector.Xna, Output, PropertyGrid and Xna.
A software rasterizer written from scratch in C#. The API is closely modelled on Direct3D 10 and 11, and is split into several pipeline stages: input assembler, vertex shader, geometry shader, rasteriser, pixel shader and output merger. It uses SlimShader to parse and execute HLSL shaders entirely on the CPU, in managed code.
DotWarp is an open source server-side 3D renderer for .NET 4.0. It can be used in a background application (i.e. one without a UI) for rendering 3D meshes into 2D bitmaps.
These are the projects and games I've worked on in the past.