This place rocks. While I can't claim to be an expert on the keyword 'this' or every difference and nuance between the four instantiation styles (functional, functional-shared, prototypal, and pseudoclassical), I definitely have a best grasp I've ever had on the topics. Perhaps in another post I'll lay out what I understand about them.
My partner and I have been sailing through the data structures sprint, which has us implementing (w/o using arrays) simple stacks, queues, linked lists, sets, hash tables, trees, binary search trees and graphs and some simple associated methods. I can't speak highly enough of how cool it's been to finally grok what these structures are, what they are good for, and (especially for achieving mastery), what they're bad at.