The Python community includes PyLadies, an international group of women developers and mentors. PyCon 2013 organizers recently helped raise $10,000 for PyLadies through a charity auction, and the funds will be used to help get more women into the community.
LibreOffice: Founded in 2010, the not-for-profit The Document Foundation (TDF) leads the LibreOffice project, a community-developed free office suite that's an offshoot of OpenOffice.org. Freelance tech writer Dmitri Popov says that his first open source contribution was an extension he wrote for OpenOffice.org, and he recommends LibreOffice to first-time contributors because of its The EasyHacks. The EasyHacks page walks newcomers through the process of contributing to the project and offers a list of bugs and feature requests to help get you started.
PostgreSQL: PostgreSQL is a well-established open source object-relational database system. Selena Deckelmann, a data architect at Mozilla and PostgreSQL contributor, explains, "We are a C-based project as well, and many of our contributors learn C while contributing, or help fixing bugs in parts of the project that are not exclusively C." She recommends starting with the PostgreSQL ToDo page and the Developer FAQ. The PostgreSQL community also has mailing lists, weekly news, and an active IRC channel.
Ubuntu: Open source evangelist Benjamin Kerensa recommends Ubuntu because the project's strong community. He points out Ubuntu's range of areas for contributors, including development, documentation, art, and support. My experience with Ubuntu supports Kerensa's recommendation.
My first Linux install was Ubuntu a few years ago, and then I helped launch and edited the first print Ubuntu magazine, Ubuntu User. Ubuntu's community is huge, international, and diverse. The project offers a wealth of online documentation to help new contributors get started, and local community teams (LoCos) can be found around the world. I've been a beta tester a few times, which means I've also contributed (albeit, accidentally) to Ubuntu by reporting bugs to the QATeam. Really, the barrier to entry doesn't get much lower than the Ubuntu project.
PC-BSD: If Ubuntu sounds interesting, but you want something a little off the beaten path, Dru Lavigne, Director of Community Development at iXsystems, recommends PC-BSD. Based on FreeBSD (which is based on BSD UNIX), PC-BSD is a relatively young desktop operating system funded by iXsystems.
Lavigne says that the PC-BSD Users Handbook makes it easy to get up to speed. "A whole chapter of the User Handbook is dedicated to the various ways one can get started contributing to the project," she says. If documentation is your thing, simply create a wiki account, and get started. "Editors review and discuss changes to help the writer clearly explain the concepts they are writing about," Lavigne explains.
If you're not ready to dive right in to PC-BSD yet, the forums and IRC channel can help you get familiar with the project community. "The project and its regular contributors work hard to keep the atmosphere friendly, nip inappropriate behavior in the bud, and provide an area where users are comfortable helping each other," Lavigne says.
Documentation: Well, documentation isn't exactly an open source project, but it is a weak spot for many of them. Osier-Mixon, Yocto Project community manager, recommends open source project documentation to first-time contributors. Osier-Mixon explains, saying, "Open source is now widely accepted and one of the biggest things missing across the board, which I read as one of the biggest opportunities, especially for those of us who are not hardcore coders, is documentation. Writing skills are always valuable, and technical writing is actually a really fantastic job."