We don't usually cover Wordpress theme on TUAW, but I think we can make an exception for the Retro MacOS Wordpress Theme. Wordpress, in case you aren't familiar with it, is a very successful blogging engine which allows users to apply various themes to change the look of their blogs. Stuart Brown decided to try his hand at creating one, and he used System 6 as his inspiration. The result is a Wordpress theme that'll bring a smile to any Mac user's Finder (Ha! See what I did there?).
You can see the theme in action here.