A lot of people talk about (and hate!) SCO now, but they used to be a cool company. They had a little office in Santa Cruz, California, complete with a redwood hottub. It wasn't unsual to see SCO engineers walking around with nothing on, going to and from the hottub!
I learned Unix one day on a whim. I was doing software developement for military contractors (around 1989), and wanted to move to the commercial sector. Unix was "hot" and I wanted to become familiar with it. So I paid about $1200 for a copy of SCO Xenix, which came in two boxes like this: