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 http://tirania.org/blog/archive/2012/Oct-22.html For the life of me I cannot work out where to get it from as a package for Linux or even Windows. This page seems to suggest it's still in Beta: http://www.go-mono.com/mono-downloads/download.html
![Installing Mono 3.x in Ubuntu/Debian](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)