Anthrocon Webform - An add-on to Drupal's Webform module. It provides a tab-delimited download for webform submissions that presents multi-selects as comma-delimited lists instead of separate fields. Very handy for fields that have 10 or more options to choose from!
Anthrocon Dealers - This is an add-on for Drupal's Ubercart module. It provides reports to our Dealers Room staff of who purchased Dealers Room tables for our convention.
Anthrocon-reg - The pre-registration and on-site registration system for Anthrocon. This software, written as a Drupal module, accepts credit cards at pre-registration, talks to Authorize.net, and drives CR-80 badge printers at on-site registration. Works well under LAMP or WAMP.
Doug's Drupal Templates - A series of user and page templates for Drupal that I wrote. They contain support for social networking sites (Facebook, Twitter, etc.), and instant messenger support in both user profiles and forum posts. I also use this module on some websites I run.