Anybody know about Citrix?? (Especially Cert. Exams)

[BillGates]

While visiting Hot Deals, I found a free voucher for a Citrix Certification Exam..... Now, I have no idea what Citrix even does, but imagine with a bit of studying, I could pass an exam, and add another set of letters on my resume Does anybody know if Citrix is worthwhile to learn, what the heck it even is, or if I should just pass up the free opportunity and not waste my time?

 

[Gunbuster]

Citrix makes Metaframe, a terminal/App server that costs lots of $$$$$