I’m involved in a couple of projects and groups, which I try to give some of my time
too. However spare time is a bit of a luxury now days 
Codeweavers
Codeweavers is a Canadian company that does a heck of a lot for the Wine community and is a bit mover in the creation of a seemless Windows Compatibility Layer for Linux and MacOSX. They produce a number of packages such as Crossover Games, Crossover Professional for both MacOSX and Linux. These are sold with support packages. Most if not all code put into Crossover products is committed to the main Wine tree. Apart from owning a copy of Crossover Professional and Crossover games and support Wine with monetary contributions, I am a Steam and Team Fortress 2 advocate. I am tasked with testing new releases, reporting bugs and helping other users. This is volunteer work done in my spare time.
Fedora
I assist Fedora developers by testing out new releases of the popular Fedora Linux operating system. Mainly bug reporting. I am also active on the Fedora IRC channels to assist other Fedora users.
CentOS
I’m an active user of CentOS and can be found trawling the forums attempting to help other users. I also troll on the CentOS IRC to assist other users. I’ve also developed a couple patches and fixes to kernel modules in the CentOS distribution.
OpenMPI
As part of my work with High Performance Computing, I am on the OpenMPI mailing list, keeping an eye on things in the Linux HPC world and helping out where possible.
Torque and Maui
I’m on the torque and maui mailing lists, where I try to help others and ask questions about my own queuing system implementations.
LinuxSA
I joined the Linux South Australia group recently to keep in touch with what’s happening in the Local South Australian Linux community.