Sorry in advance for the long post. I've just finished putting together the bones of my second Drupal website, http://www.kfol.org/. I've been debating whether, in its crude state, it warranted showcasing to the Drupal community. Well I decided it does, but not for the site itself, rather for the great modules it uses.
First I'll say a little about the site's purpose and structure, then I'll explain how I accomplished it with what modules. I don't know the first thing about CSS and theming, so I used the contributed Barron theme by jwolf. I think it's a fabulous theme for my purposes, but I'm well aware that my site is not likely to win the look and feel award of the year. (No offense to Barron's designer.)
Knowledge Farm is intended to be a framework for community contributed "how to instructions" classified in a folksonomy. I wanted users to have the ability to "sponsor" sets of instructions to develop them with community feedback, possibly into "open source" products. Additionally, I wanted users to be able to rate and comment on content, so that instructions with problems might be easier to identify.