Slackware (and, I'm pretty sure, a pre-1.0 kernel) was the first Unix I saw, in '94 or '95, for http://www.ticalc.org/. A few guys invited me to help them build what would become the de facto TI graphics calculator community, but I lacked sufficient clue. Since I had a Mac IIci, one of them suggested I install NetBSD and learn up. Getting involved with NetBSD eventually led to friends, travel, college, jobs, etc. Amazing how life happens.

Semi-related: in 2003-04, I worked a couple floors up from Chet Ramey. A college buddy was a big fan of Chet's Emacs. editors/ce (and editors/ce-x11) wound up being some of my first commits to pkgsrc.