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
Grasshopper enables .NET developers to cross-compile Microsoft IL (i.e.: the output of any .NET programming language) to
Java bytecode, using the open source Mono Project's class libraries.
ServiceStack JsonSerializer is based on JSV (the fastest text serializer for .NET), and is over 3.6x times faster than the BCL
JsonDataContractSerializer and is around 3x faster than NewtonSoft JSON.NET (the previous fastest JSON serializer benchmarked).