I am a big fan of open source software. Nearly everything I use is open source. I run Xubuntu on my work computer, and Ubuntu or CentOS on most of my servers. Most of my servers are a LAMP (Linux, Apache, MySQL, PHP) stack. Eclipse is my preferred development environment. My contribution to the open source community has been pretty slim so far but it is increasing.
The majority of my open source contributions have come in the form of mods or sub-games for an open source Mincraft clone called Minetest. My more notable contributions are the Landrush area protection mod and the Adventuretest sub-game. These are all written in Lua. I also maintain a custom minetest client for Adventuretest. I still consider myself and active part of the community but my time spent on Minetest varies greatly depending on the amount of work I have so sometimes these projects can lay dormant for months at a time until I have more time to devote to them.
All of my open source work can be found on GitHub. There you will find my Minetest mods and sub-games. There is also a basic MVC framework for PHP I am developing and have started using heavily. It is simple called bremaframework. I forked a project management / task list program called streber. It’s master branch has laid dormant for nearly two years so I am trying to revive it mostly because it is what I use and there are features and fixes I want to see. I started writing a web-based RPG, it has laid dormant for about 3 years, and it may be completely broken at this point but it is on GitHub as well under the name bremarpg. It’s one of the projects I hope to start development on again. I have a few other projects I plan on open sourcing once they are ready for release or close to ready.