The Common Language Infrastructure (CLI) is the ECMA standard that
describes the core of the .NET Framework world. The Shared Source CLI is a a
working implementation of the ECMA CLI and the ECMA C# language specification.
	This implementation is released under a shared source initiative. Please
see the accompanying license.
	The Shared Source CLI goes beyond the printed specification of the ECMA
standards, providing a working implementation for CLI developers to explore and
understand. It will be of interest to academics and researchers wishing to teach
and explore modern programming language concepts, and to .NET developers
interested in how the technology works.

Features:
o An implementation of the runtime for the Common Language Infrastructure
  (ECMA-335);
o Compilers that work with the Shared Source CLI for C# (ECMA-334) and JScript;
o Development tools for working with the Shared Source CLI such as
  assembler/disassemblers (ilasm, ildasm), a debugger (cordbg), metadata
  introspection (metainfo), and other utilities;
o The Platform Adaptation Layer (PAL) used to port the Shared Source CLI from
  Windows XP to FreeBSD;
o Build environment tools (nmake, build, and others);
o Documentation for the implementation;
o Test suites used to verify the implementation.

WWW: http://msdn.microsoft.com/net/sscli/