Reverse-Engineering Xkcd's 'Frequency'
Not super related to the content, but I love the "Show Code" button at the bottom of the article. So often sites either show code inline and break up my reading, or just dump the whole thing into a github repo, which loses context.  That button is awesome, because I can read the whole thing to understand the problem, then review the code the next time through with better context.Awesome!