Python user since 1997, starting as a replacement for cgi-scripts written in C++.
While managing the distributed development of the plug-ins for Pinnacle Studio I used Python mostly as the glue to make CVS an acceptable Version Control System ( which was the topic of my talk at Pycon 2006 http://www.xs4all.nl/~anthon/pycon2006/ ).
There Python is also the implementation and configuration language for the Sanbox build system I developed. That system overcomes the problems associated with the lack of revisioned metadata in CVS and has several advantages over they way (non-portable) revisioned metadata is stored in other VCSs. The Sandbox system also makes it possible to gradually change large codebases from one VCS to another. That system has been running in multiple locations for over 10 years now.
I have been using web2py quite intensively, but due to changes in the internal structure (which I relied upon for getting acceptable performance) are stuck on an old version for my major project. Currently looking at something that does support Python 3 as web2py does not seem to go that way (fast enough to my taste at least)
I have done wxPython development, choosing that toolkit over others to get a portable native look-and-feel.
I have contributed to several python based open source projects. Sometimes just for the fun of, sometimes because I want to learn the internals or usage project, sometimes because I needed the changes for my own software development. Among the python based projects are tox, py.test, pyjamas (pyjs), argcomplete and others.
I also implemented a (fast) C version of Foord and Larosa's OrderedDict (before the subset of the functionality became available in the standard collections module).