June 6, 2011 - "World IPv6 Day"

Just heard about this, very interesting and cool!

Facebook, Google, Yahoo commit to 'World IPv6 Day' trial
Internet Society attracts key sites to 24-hour test of next-gen Internet services

By Carolyn Duffy Marsan, Network World January 12, 2011 09:02 AM ET

Several of the Internet's most popular Web sites - including Facebook, Google and Yahoo - have agreed to participate in the first global-scale trial of IPv6, the long-anticipated upgrade to the Internet's main communications protocol known as IPv4.

From NetworkWorld article.