xacc.ide is a opensource IDE aimed at mainly .NET development. It has a code editor written in 100% C# code, which is faster than most commercial offerings.
LispSharp is a fully compiled lisp implementation for the .NET Framework.
It uses a Lisp dialect similar to ISO Lisp, it has a Command-line toplevel
compiler with Read Compile Print Loop.It references any .NET DLL and produces standard .NET assembly.
CLearSharp is a clean C#-implementation of Common Lisp. The big goals are ANSI standard compliance, interoperability with Java and integration with scripting environments. This project is meant to be a sibling to CLearJ, with sharing of implementation.