That's how I got started in Unix. As part of an overall upgrade my employer at the time bought a couple of Sun Sparc workstations to act as servers for our PC network. After a couple of years working there, I went on to get a job with another place as a full-time SunOS/Solaris admin.
This new job that I'm applying for would be as a Linux/Solaris admin (emphasis on the Linux). I haven't worked much with Linux, but the boss knows me and knows my work, so I may have an "in"... I hope I do anyway!
I love working on SunSparc machines. I am not at liberty to tell you what all we used 'em for, but WOW are they cool!