Kind of far-fetched, but hey: years ago I saw a web page which was plain HTML (ie. without CSS), and step by step it was turned into something beautiful and readable with a few CSS rules (adding margins, increasing font size, that kind of basic typography stuff). I seem to recall it was meant to teach both basic CSS and basic typography.
Does anyone have a link or remember anything about the title or the author, so I can find it? I just find random CSS tutorials.