Here's my spontaneously-developed-while-standing-around-in-the-ICU metaphor for learning.
   In the course of listening to a Spanish family, I realized that as long as they were talking slowly I could understand at least a good three-quarters of what they were saying; there's no way I'd be able to speak Spanish or repeat any of it, but for some reason today it suddenly became sensical. In reading my teach-yourself Arabic script book, I'm starting to realize that each time I learn another bit of the way the protean alphabet works and smatterings of grammar, the tickers on clips of Al-Jazeera on the news are slowly starting to become recognizable
   In any case, my metaphor (spawned by those "clicks") is that learning about a particular topic is like trying to see a magic-eye/3-d picture. I can look at Wyatt's rockets, Scott's electronics, or even Xuemei's wall-filling biochemical pathways chart and just see a big wash of static, as it were. But they can each see thrust vectors and ways to rebuild things and information in a tangle of colored lines; and I can look at a poem or language, or aikido technique or whatever and maybe see something they can't. So as we all learn about each of the topics, they slowly start to take shape in our head till it eventually it gets to the point where we can see every angle of it when it lifts off the page entirely. As it were.

Dubious, but interesting - It's gotta be the hat

Longish, but nice bits of history mixed with linguistics -Hebrew alphabet