people who want to run .net on linux.
Mono provides the necessary software to develop and run .NET client and server applications on Linux, Solaris, Mac OS X, Windows, and Unix. Sponsored by Novell, the Mono open source project has an active and enthusiastic contributing community and is positioned to become the leading choice for development of Linux applications.
There are many applications available that run on Mono
MonoDevelop is a free GNOME IDE primarily designed for C# and other .NET languages.