On this page, you can find a suite of demo programs that shows how to use Tk widgets with Tkinter. This suite is the Python version of the one written in tcl and distributed with tcl/tk, often referred as widget tour.
The main module of this demo suite is widget.py ; running it, you get a graphical menu which allows you to start the demo programs. Each demo is a single module: you can see its source code by clicking on the see code button; you can also modify the source and rerun it.
If you are looking for Tkinter code samples, fill free to download the whole suite using one of the links in this page:
the file widget-tour.tar.gz is the original demo suite, which works with python 2.x.
the file widget-tour-py3.tar.gz is a port of the same demo programs to python 3.x.
The files are distributed under a 'please help yourself' licence. Enjoy 
The suite is not complete yet: it covers about 80% of the original one (with some bugs). And it is always be possible to extend it with new demos. If you want to contribute, post your change proposal on the TkinterDiscuss mailing list.