First, references will be added to the CLR assemblies that will be used.

import clr
clr.AddReference('System.Windows.Forms')

Next the names we will use are imported.

from System.Windows.Forms import Application, Form

A class will be created for the Hello World form using Form as its subclass.

class HelloWorldForm(System.Windows.Forms.Form):
    def __init__(self):
        self.Text = 'Hello World'
        self.Name = 'Hello World'

The text attribute of the form sets the title bar's text.

To run the application, we create an instance of the HelloWorldForm.

form = HelloWorldForm()
Application.Run(form)

The Application class provides static methods and such as starting and stopping an application. The Run static method runs the form on the current thread.