I\'ve recently read that Mono 3.0 has been released with a C# 5 compiler and support for MVC 4 here:
http://www.mono-project.com/Release_Notes_Mono_3.0
and<
There is now a link to a Windows installer for Mono 3.0.1. Unfortunately it doesn't seem to install on Windows 7 64bit. You may have better luck.
http://www.go-mono.com/mono-downloads/download.html