The FreeBSD Project
I was a core team developer for FreeBSD from 1994 to 2000, but my involvement began much earlier, in a precursor called 386BSD. 386BSD was the first port of BSD Unix to the Intel platform, authored by Bill Jolitz, who was contracted by Berkeley to do the Intel port. I performed testing and contributed patches to his first "noname" release. Later on, I was involved in a subsequent "patch kit" for 386BSD that accumulated contributions of developers as the following grew. This "patch kit" represented FreeBSD in it's earliest form. Being on the FreeBSD core team was an exciting experience, especially the opportunity to see FreeBSD in use at places like Yahoo and Hotmail in their formative years.
One of my principal interests was FreeBSD's support for the XFree86 window system in the form of console drivers, access to video hardware, general platform support, documentation and release engineering. This was, to me, a form of stewardship in that it was an opportunity to contribute to the productivity of other developers by making it easier for them to use FreeBSD as a desktop.
These days I focus mostly on the Asterisk VOIP telephone system on FreeBSD.