Yahoo has released several ui libraries. Open APIs are pretty cool, but free (Creative Commons) code gives you more options. I've been considering a redesign of this site for quite some time; the ajax, animation, and dom libraries might be of some use. They've also released a series of user interface guidelines that they call 'design patterns,' which I found interesting in that such things are now considered important enough to share.
I saw this interesting post over on Jon Udell's blog that shows how you can modify your CSS to automatically include images and text before or after a <pre> or <blockquote> tag. He even goes as far as to insert of the photo of the person who made the quote. I'll have to go through some of my old entries and see how this can be of some use. I also didn't realize that you can assign multiple classes to an element, which should help pare down the size of my stylesheet.
- Jon's Radio
Also, mezzoblue is the best looking blog I've ever seen.
Update: Eric Meyer kindly pointed out that CSS Zen Garden is Dave Shea's work (sorry for the improper attribution - both of you have great sites!).