It is the yearly CSS naked day! This is when we strip off our style sheets and expose the bare truth of our HTML.
I did so last year and I am still quite proud of how good mine looks naked. :)
The reason for this annual event is to emphasize the importance of a well structured, semantic HTML foundation. This increases the usability of your site and makes it easier/possible for all visitors to participate. This is still important stuff.
Are you participating?