From Drupal and Moodle, right through to a Git versioning system and Perl modules on CPAN, we contribute back to over 175 community open source projects. This list is in order of the number of projects contributed to.
For code related to making ePub files
A complete packaging of Evolution Data Server for Maemo, including the addressbook, calendar, and email library (Camel).
Faker (aka fake-factory) is a Python package that generates fake data for you. Whether you need to bootstrap your database, create good-looking XML documents, fill-in your persistence to stress test it, or anonymize data taken from a production service, Faker is for you.
Run a Git command in several repositories
This script allows you to create archive that includes entire repository (including all submodules)
A bidirectional Git - Bazaar gateway
git-bzr shell (https://gitorious.org/git-tools/git-bz)
Fork of http://github.com/pieter/git-bzr … rewritten in /bin/sh
A gem that processes Trello cards from Git post-receive hook