
PHP
When I first started working with the Population Research Institute, their website relied on a proprietary content management system. Their site offered hundreds of articles, but they were full of hard-coded formatting like fonts, heading sizes, and colors (such as purple). Many hours of Perl and proofreading later, PRI had a new Joomla site with a clean, consistent look.
Joomla served them well, but fortunately, by the time they discovered the real constraints, I had discovered Drupal.