Our company uses RT (Request Tracker) for long time and I play sometimes with it to customize for our business.
RT is an enterprise-grade ticketing system which enables a group of people to intelligently and efficiently manage tasks, issues, and requests submitted by a community of users.
RT is a pure Perl application and in my mind it can be shown as the best example of OOP on Perl! As template system RT uses Mason – the most power and famous template system for Perl.
Recently I’ve discovered that O’Reilly is going to publish a book about RT – RT Essentials. The book is coming to order in August. So, that book will be helpful to understand how develop and customize RT.