Here are some links I've been using recently related to CSS:
1. colorpeek.com is a nice tool to create a color palette and to share it.
2. Colors by commutercreative.com is a neat tool to visualize the 147 named colors in CSS.
3. On-Off switches made with CSS only ... pretty cool.
4. For generating gradients (and other neat CSS-related stuff), check out the excellent westciv.com from John Allsopp.