Installing Mono and ASP.NET on Raspberry Pi

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install mono-complete
mono --version

To install Mono Develop:

sudo apt-get install monodevelop
sudo apt-get install mono-xsp4