World IPv6 Day is 1 week away, and for what it's worth, I'm joining in. On Wednesday 8th June, if you visit my site or any of the other participants, such as Google, you'll be helping to test whether mass deployment of IPv6 is likely to break anything.
Here's a good explanation of the experiment. The tl;dr version: you probably won't notice any difference; you can try it out here; if you discover on Wednesday that you can get to Google but not to my site, then it's more important than usual that you tell me.
Oh, and if the experiment doesn't appear to cause anyone any significant problems here or elsewhere, then I may well leave it in place (plenty of sites have already been doing the same for years).