OT: HP-UX Certification?

So things are kind of slow at work right now and I thought I'd study
towards another certification to pass the time. I've been using HP-UX
10.20 at my current job for the last several months and I've gotten pretty
comfortable with it, so I thought I'd ask around and see if there are any
people on this list that are HP-UX Certified. If so, what topics would
you recommend that I focus on to prepare for the test? What was your
overall impression of the test? Any other info/advice would be greatly
appreciated.
Thanks,
~M