Python Module of the Week by Doug Hellmann
Update (20130225): PyMOTW has moved to http://pymotw.com. Update your bookmarks.
“PyMOTW is a series of blog posts written by Doug Hellmann. It was started as a way to build the habit of writing something on a regular basis. The focus of the series is building a set of example code for the modules in the Python standard library.”
Doug guides you through the Python standard library with lots of examples. Definitely a must read!