Ping it to light it up!
2a05:2d01:2017:4242::AA:BB:CC for HTML Color #AABBCC
2a05:2d01:2017:4242::FF:00:00 for color RED
2a05:2d01:2017:4242::00:FF:00 for color GREEN
2a05:2d01:2017:4242::00:00:FF for color BLUE
2a05:2d01:2017:4242::FF:FF:FF for color WHITE
... and so on...
Every ping packet flashes a random LED in the requested color.
Keep in mind there is about 10 to 15 seconds streaming delay on youtube
You won't get a ping reply (saves me bandwidth) but in the livestream you should see LEDs flashing for every packet received.
Update August 2017:
The IPv6 Christmas Tree is back for a few days!
Since we are currently camping at #SHA2017 (a big outdoor hacking camp in The Netherlands) and have a surplus of bandwidth, the tree is alive again.
Internet uplink is +100Gbit/s here. Please try to ping it as much as possible! :-)