One more challege defeated! Turns out that there is no native way to just get a list of the most recently commented posts in the sidebar, so I had to get a plugin. Luckily, this is a fairly common requirement, so there are several plugins to choose from. Unluckily, most people want to do something different – they want to list the most recent comment as an excerpt in the sidebar, which I don’t really like. But I did finally find a post to do what I wanted (as you can see in the sidebar), with Coffee2Code.com’s Customizable Post Listings plugin.
Next challenge: making an offset lists of posts, confirming that I have all the archive pages I need and getting some basic site stats up.