I've contributed a number of modules to the Drupal web application framework. You'll find most of these on Drupal's website.

The others are checked into my drupal sandbox. You'll find the code there, and more documentation here. If you encounter problems with any of my sandbox modules, please post an issue here. (Although I may not be able to help. If the module is in my sandbox it usually means I don't plan to support it, except to the extent that I use it myself.)