They always say reading code is the best way to sharpen your skills in a given language, why don't we try that out? I think of this as sort of a book club for source code. We'll break down a couple of functions, discuss architecture and just generally fool around in inspector :)
Trying this out for the first time with d3.js:
To isolate the functions we'll be looking at run the following in the console http://jsfiddle.net/P3AzY/ then you can access it through the d3 variable.