css

Jetstrap - The Bootstrap Interface Builder. Maybe check it out - with this you can design Bootstrap sites in their structure without having to fiddle with the CSS yourself. The output can then be used as a basis for your own website. Looks quite nice.

Pure CSS GUI icons (experimental) are an excellent example of what you shouldn't do with CSS. Painting with box models is rather unproductive. But somehow it's still fascinating what some people do with their time ...

Sass - Syntactically Awesome Stylesheets - I'm not sure if I'm so enthusiastic about it yet, but it's basically a preprocessor for CSS that offers various extensions that make it easier to write complex CSS.

CSS Homer, animated - some people just have too much time ...

Reset Reloaded - an interesting approach to the CSS default differences of various browsers: simply reset everything cleanly, so that stylesheets can start on a common basis.

CSS Fisheye - CSS magnifying glass effect in a text block.