Half a year ago I accidentally uploaded a hideous redesign and decided to keep it so that I would be motivated to get things fixed. This plan didn't work quite as well as I had hoped.
The new CMS went live this afternoon though, so fingers crossed that is is going to run smoothly.
It is written in Perl (currently running on Perl 5 version 18.1) with Catalyst and uses FastCGI with a MySQL backend (because that is what my hosting has available). The source code is available on Github.