Ownacolour.com is worth a click just because your eyes will thank you. If you buy a color, some child somewhere in the world won't thank you because they won't have any idea about it, but you can feel good about yourself and do some good.
The site is run by Glidden paint and Unicef. It's pretty well executed idea. It's satisfying experience to click around and it's a simple idea. A great example of using the web for it's inherent 'web-ness'.