Singleton done properly for 99% of needs Jon Skeet (http://pluralsight.com/training/Courses/TableOfContents/csharp-design-strategies)

Singleton.cs

public class Singleton
{
   private static readonly Singleton instance = new Singleton();

   // Empty static ctor forces laziness
   static Singleton()
   {}
   private Singleton()
   {
       // STuff that must only happen once
       Console.WriteLine("Singleton Constructor");
   }

   public static Singleton Instance { get { return instance; } }

   public static void SayHi()
   {
       Console.WriteLine("Hi");
   }

   public void DoSomething()
   {
   }
}