All of you must be aware of what Singleton Design Pattern is. Just to define it in one line, It is a pattern which allows creation of one and only instance of a class.
The practical scenario where you can go with this pattern is having a print job class instance, single running instance of an application etc.
The best example is Google Talk desktop application.
Let us try to implement this pattern via C# code.
The Singleton class above will be instantiated only once.
When the GetInstance is called, it will return the statically created instance of the class.