[http://vpython.org VPython] - 3D programming for ordinary mortals
[http://www.alcyone.com/pyos/chess Chess] - a chess adjudicator module
[http://nltk.sourceforge.net NLTK] - Natural Language ToolKit
[http://epydoc.sourceforge.net epydoc] - API documentation generator for Python modules
SLCrypto is a package for Python that dramatically eases the task of adding encryption to Python programs. [http://www.freenet.org.nz/python/SSLCrypto/]
[http://pages.cpsc.ucalgary.ca/~aycock/spark SPARK] - Scanning, PArsing and Rewriting Kit
[http://www.lemburg.com/files/python/mxTextTools.html mxTextTools] - a fast text manipulation toolkit for Python
[http://simpleparse.sourceforge.net SimpleParse] - a parser generator for mxTextTools v2.0.0
[http://mayavi.sourceforge.net/ MayaVi] A library and application for scientific visualization based on VTK.
[http://systems.cs.uchicago.edu/ply/ply.html PLY] - a Python-only implementation of the popular compiler construction tools lex and yacc
See LanguageParsing for more tools.