How to compile a C# program on OSX?

How to compile a C# program on OSX?

Let's start with level noob because that's where I'm at
// Hello.cs
public class Hello
{
public static void Main()
{
System.Console.WriteLine("OM NOM NOM NOM");
}
}
Guys, I'm on hungry, but I'm on a Mac using OSX. I'm not unfamiliar with
computing machines but I am curious if it's possible to compile this bit
of code using OSX.
Disclaimer I don't want a big fat IDE. I'm basically looking for the
equivalent of
$ gcc hello.c -o hello
$ ./hello
OM NOM NOM NOM
$
But, you know, for C#.



If you recommend a package (e.g., mono) please demonstrate usage! I'm not
marking an answer as accepted until I see a compiled/running Hello World
program.