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.
Piwik is an open source (GPL license) web analytics software. It gives interesting reports on your website visitors, your popular pages, the search engines keywords they used, the language they speak… and so much more. Piwik aims to be an open source alternative to Google Analytics. The software is used by more than 50,000 active users, is translated in 40+ languages and is actively growing. Check it out!
Plack is a Perl module and namespace that contains a set of reference server implementations, middleware and utility modules for PSGI, Perl Web Server Gateway Interface.
PostgreSQL Database Server (http://www.postgresql.org/)
PostgreSQL is a powerful, open source relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, Mac OS X, Solaris, Tru64), and Windows.
yet another forking process controller
Puck's Gnucash Tools (http://www.etc.gen.nz/projects/gnucash)
Tools for working with Gnucash. Such as loading txn information into a CalDAV calendar.
SOFA Statistics (http://sofastatistics.com)
SOFA is a statistics, analysis, and reporting program with an emphasis on ease of use, learn as you go, and beautiful output.
A simple web search client for performing SRU searches on Fedora.
SSHMenu is a GNOME panel applet that keeps all your regular SSH connections within a single mouse click. SSHMenu can be used outside of GNOME too.
Scapy is a powerful interactive packet manipulation program. It is able to forge or decode packets of a wide number of protocols, send them on the wire, capture them, match requests and replies, and much more. It can easily handle most classical tasks like scanning, tracerouting, probing, unit tests, attacks or network discovery (it can replace hping, 85% of nmap, arpspoof, arp-sk, arping, tcpdump, tethereal, p0f, etc.). It also performs very well at a lot of other specific tasks that most other tools can't handle, like sending invalid frames, injecting your own 802.11 frames, combining technics (VLAN hopping+ARP cache poisoning, VOIP decoding on WEP encrypted channel, ...), etc.
Selenium Builder (http://seleniumbuilder.github.io/se-builder/)
A test development environment for Selenium 1 and 2