Lifewiki is a project mainly written in PERL and CSS, it's free.
LifeWiki, a Mason/Perl based wiki
Welcome to LifeWiki.
Eventually this document will contain a bit about the software, but maybe that's irrelevant if it's never going to have public source release.
If you're setting this up somewhere, the incantations that you should know to get your httpd.conf setup correctly are:
Obviously you'll have to setup other stuff (User, Port, Group, start servers, logging, etc) to suit your needs. You'll also want to look at the etc/config.pl.example and then copy that to etc/config.pl and set it up appropriately.