The Drupal CMS (PHP, GPL) allows you to assemble powerful web sites instead of writing them from scratch. It supports custom inter-related data types, configurable views and summaries of all content, user-generated content, search, user accounts, roles, media handling, and much more. Thousands of contributed modules provide all kinds of functionality.Eventually, though, many sites need custom functionality. For those who didn't make the April User Group, you can Listen Now! to Barry Jaspan, Principal Engineer at Acquia, Inc. as he takes us on a deep dive.