I enjoy the tilde.club site/community, and since I've just setup an IPv6-only host I was looking to do something similar.
Unfortunately my (working) code to clone github repositories into per-user directories fails - because github isn't accessible over IPv6.
That's a shame.
Oddly enough chromium, the browser packaged for wheezy, doesn't want to display IPv6-only websites either. For example this site fail to load http://ipv6.steve.org.uk/.
In the meantime I've got a server setup which is only accessible over IPv6 and I'm a little smug. (http://ipv6.website/).
(Yes it is true that I've used all the IPv4 addreses allocated to my VLAN. That's just a coincidence. Ssh!)