Just because my examples happen to be in CommonLisp don’t let that say anything about ZeroMQ. It runs FREAKING EVERYWHERE and the API is small enough that remembering it is entirely separate from whichever language you use it in.
Now go read The Guide or check out my much shorter-than-the-full-guide crash course/introduction presentation slides HERE. It’ll also quickly gloss over Mongrel2.
EDIT: 280slides is going down! Here is a Scribd mirror: 0MQ and Mongrel2 Overview Talk Slides