We have talked abut CSS Zen Garden in past sessions of our workshop. News today is that CSS Zen Garden is amazingly now ten years old. This site has been one of the great showcases of what can be done with cascading style sheets over good clean HTML.
In celebration, founder Dave Shea has re-opened the site for new submissions. There are new requirements, as pointed out in the blog post, and of course the possibilities are wider than ever with HTML5 and CSS3.
Give it a try.