Programs that aren't (as far as we know) written in Python, but which you can script in Python:
[http://www.ciranova.com/products/ Ciranova's PyCell Studio] (a tool from an Electronic Design Automation company)
[http://civilization4.net/files/modding/PythonAPI/ Civilization IV]
[http://www.gimp.org The GIMP]
[http://www.atari.com/toee/ Temple of Elemental Evil]
[http://www.openoffice.org/ OpenOffice] (explain PythonUno)
[http://www.scribus.net/ Scribus]
[http://vimdoc.sourceforge.net/htmldoc/if_pyth.html#Python The vim editor]
Emacs, using [http://pymacs.progiciels-bpi.ca/ Pymacs]
[http://www.gnome.org/projects/orca/ Orca]: Using various combinations of speech synthesis, braille, and magnification, Orca helps provide access to applications and toolkits that support the AT-SPI (e.g., the GNOME desktop).