Would you like one of these very pretty logos on your webpage? Given my Irish passport I'm committed to having green as my favourite colour even if it doesn't work with my blue background, but alas, I'm not a graphic designer.
The logo is assigned to invididual websites who are accessible via IPv6. If you are running a website which is IPv6 capable and want to help spread the word, then you can jump over to IPv6 Forum's Enabled Program and test your site according to their specifications. They also provide a dynamic logo which informs the user if they are accessing over IPv4. You can see an example of this logo at my home site, www.cunningtek.com
Additionally, you can also get this nifty, but admittedly, not as pretty logo from 6bone here.