Idea: make a beautiful puzzle globe for the event! Last done at the 07 wikimania w/ success; since then we have much more experience w/ printing generally (and 3d printing + construction + lightweight materials have come a long way).
We can aim for both largest 3d puzzle (phsyically + most pieces) and largest 3d shape collaboration. Current largest fit together to make a Honda, 4m long and 1.5m wide + tall. Anything we build that's tall enough to walk inside would be a world record.
The bones of the substructure can be geodesic, making it easier to ship + construct. Each [triangle] of the geodesic can itself be a little 3d puzzle, making up the underlying structure.
Invite different groups to volunteer to make and bring individual panels out of a material of their choice
The outward facing surface panels can be snap-on, w/ 2.5D shapefiles (limited range of depth),
Easy to 3d printspare panels so there's a guaranteed full cover + a 'vanilla' version that can persist or be installed somewhere on permanent / rotating exhibit
The finished puzzle should be taller than a person, so people can walk into the middle
Cool things could happen inside the globe ... which we've never seen inside ;) UNTIL NOW!
If the outward panels are ~flat and determined by the current logo, cool 3d elements of the internals can point inwards, to be viewed from inside. [representative of different regions?]
Consider a projector setup in the middle of the globe, with multiple projectors and translucent sphere surface (imagine a transparent interior and translucent surface paper) so that the display on the sphere is updated dynamically.
This could be slowly updated – taking time to prepare something that maps onto the specific geometry – or rapidly, taking ~30 small images and projecting them onto the ~30 individual puzzle pieces
This is not Wikipedia conference, but Wikimania is a Wikimedia conference, where every projects are celebrated. Let's not just focus on Wikipedia, but rather all other projects that are under Wikimedia: Wiktionary, Wikisource, Wikibooks, Wikiquote, Wikiversity, Wikivoyage, Wikispecies, Wikinews, Wikidata, MediaWiki, Wikimedia Commons, etc.
Since there's no existing design of such globe, I would suggest the original Wikipedia globe, but instead of the various script of the world on each puzzle piece, we could put the various project logos on them. Since the number of puzzle pieces > number of distinct Wikimedia project, we could brainstorm what else to put there.
If the globe is big enough, each puzzle piece could also contain a QR code, so people can scan each Wiki project to know more about them.