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.
Archimedes Server (https://github.com/fiasco/Archimedes)
Application Monitoring Server Built with Drupal
This Perl module provides an API for integrating your application with the New Zealand igovt logon service using SAML 2.0 messaging. The distribution also includes a command-line tool called 'nzigovt' which can be used for generating certificates and metadata; generating authentication request messages and resolving artifacts.
BCVI is a command-line tool that works with SSH to provide a 'back-channel' from the server you have connected to, back to your workstation.
Bacula is a set of programs that allow you to manage the backup, recovery, and verification of computer data across a network of different computers. It is based on a client/server architecture and is efficient and relatively easy to use, while offering many advanced storage management features that make it easy to find and recover lost or damaged files.
Benchw provides a toolset to benchmark the capabilities of several different database engines for data warehouse type activities. It is designed to provide a simple way to test data loading, index creation plus query performance in the spirit of TPC-H
An object-oriented library written in PHP that allows reading and writing iCalendar files. It is easy to use, fully standards compliant, and powerful. Intended audience: application developers who want to support iCalendar (RFC-2445, iCal).
Bizgres is a PostgreSQL "distribution", including experimental core mods, for an optimized Business Intelligence version
Booktype (formerly known as Booki) is the open source platform that helps people write and publish print and digital books. Booktype makes it easier for people and organisations to collate, organise, edit and publish books. Delivering frictionlessly to print, lulu.com and almost any ereader, Booktype facilitates collaborative production processes. No more lost manuscripts, overwritten Word files, awkward wikis or cumbersome CMSes. This project is related to https://www.ohloh.net/p/objavi
CERN Central Library bookmark redesign (http://l0b0.wordpress.com/2010/07/27/library-bookmark-redesign/)
CPAN-API (metacpan backend) (http://www.metacpan.org/)
A free, open API for everything you want to know about CPAN. Also serves as the backend for the metacpan.org web site.