Nice site, though it's a bit much to claim most of those pages as triumphs of CSS when really it's just chunks of pre-rendered art.

My favourite website is Wikipedia too, but since onebyone has already nominated it, I don't need to.

So, since the idea is to introduce people to cool things they might not have seen, I nominate: The Internet Ray-Tracing Competition ! Amazing techniques for graphics geeks combined with eye candy for everyone.