OWIN defines a standard interface between .NET web servers and web applications. The goal of the OWIN interface is to decouple server and application, encourage the development of simple modules for .NET web development, and, by being an open standard, stimulate the open source ecosystem of .NET web development tools.
These projects provide documentation and resources to help you start using OWIN. If you'd like your project listed here, please post on the discussion list.
Katana - OWIN implementations for Microsoft servers and frameworks.
Read more: OWIN