A Usefull PyGTK Example

I have been looking for a good pygtk tutorial for a very long time. I have found a few tutorials which where an overkill, so I don't link to them. By over kill I mean that they where full with details which prevented me from actually having an application working.
I found this nice pygtk tutorial, which is actually more a capabilities demonstration. After reading for a few hours, I got intrigued. But I was very frustrated since the tutorial does not produce any real life example. For example, I would have expand the calculator example to working one. I did a Google search and bumped into this pygtk calculator working example. After a couple of more hours, I have managed to produce the following "Hello World!" pygtk application which demonstrates some basic pygtk principles:

#!/usr/bin/python

# A Usefull and Active PyGTK Example
#
# This example demonstrates a few Widgets which actually do 
# some stuff, and interact with each other.
#
# oz nahum
# linuxpixies.blogspot.com 
# August 2011

import gtk

class PyApp(gtk.Window):

    def __init__(self):
        super(PyApp, self).__init__()
        
        self.set_title("Entry")
        self.set_size_request(250, 200)
        self.set_position(gtk.WIN_POS_CENTER)

        self.fixed = gtk.Fixed()

        self.label = gtk.Label("Please Enter Your Name below")
        self.fixed.put(self.label, 60, 40)
        
        self.entry = gtk.Entry()
        self.entry.add_events(gtk.gdk.KEY_RELEASE_MASK)
        self.fixed.put(self.entry, 60, 100)
        
        self.entry.set_text("bla")
        self.UserName=self.entry.get_text()  

        self.outlabel=gtk.Label('name')
        self.fixed.put(self.outlabel, 60,180)
        
        self.button = gtk.Button("Greeting:")
        self.fixed.put(self.button, 60,140)
        self.button.connect("clicked",self.greeting)
        
        self.clearbutton = gtk.Button("Clear")
        self.fixed.put(self.clearbutton, 140,140)
        self.clearbutton.connect("clicked",self.cleartxt)
       
        self.button = gtk.Button("Close")
        self.button.connect("clicked",gtk.main_quit)
        self.fixed.put(self.button, 200,140)

        self.connect("destroy", gtk.main_quit)
        self.add(self.fixed)
        self.show_all()
        
    def greeting(self, event):
        self.outlabel.set_text("Hello "+self.UserName)
        self.entry.set_text('Hello '+self.UserName)
        
    def cleartxt(self, event):
        self.entry.set_text("")

PyApp()
gtk.main()