New Great Building: The Guizhou Radio Telescope (a.k.a. FAST - the Five-hundred-meter Aperture Spherical Telescope)
It would probably have to be a fairly sizable GB and produce Forge Points and create a new special ability... like a small chance of getting a small amount of Diamonds upon Town Hall collection, increasing amount and probability upon leveling up. It would also allow the Guild HQ's controlled by the High Elves and Santa's Workshops to receive messages from Santa while he sleighing through the cosmos to visit other stars systems and gather new cool toy ideas.
I'll be hosting our annual Christmas in July bash in Dunarsund if you wanna party with special guest, Frosty - appearing for a limited time only!