I know that as a sysadmin you can contribute to opensource projects such as a Debian and Fedora. Joining their infrastructure groups and help with administration. I'm just wondering if there are any other interesting opensource projects/communities. To which sysadmin with a free time can contribute and sharpen his skills.
While a good question, the options are endless. I tend to try to contribute to things I use and find useful, while focusing on projects that are especially in need of assistance. Inprotect is a team that could definitely use some additional assistance.