The SitePoint Forums community has recently organized a CSS website design competition called The Beauty of Style, very much in the style of CSS Zen Garden. If you're thinking of taking part, sorry, the submission date is over, and judging is currently in progress.

You can take a look at the submitted entries though. Some of them are very good, like Crispy, Zanzibar, Lichen, SP Style and The Box (slightly broken in Mozilla).