You can also spend your time writing scripts, and generally "poking" around (without breaking anything
). Look for ways you can automate processes. If you have a spare PC or x86 server, install Linux (or even Solaris 10 x86) on it, and play around with Apache, BIND, Sendmail, Postfix, MySQL, Squid, etc - learning some of these applications will always benefit your resume.
Even now after working with UNIX for
many years, I'm still continually learning more. Just "playing" with my systems teaches me a great deal, and looking for new ways to solve already solved problems also is a great learning tool (i.e., can xyz be done smarter?). Perform security audits of your servers. Check for best-practices. Be curious!
Good luck!
Cheers
ZB