Had the thought of a recreational object that gave either construction or crafting skill while using. Perhaps redundant as there endless methods of more efficient ways to teach either skill. But if it were only obtainable by purchase, it could be made a mid/late game item, at which point I presume it would be mostly for fun, decoration, or perhaps to aid any skill decay from idle workers.
The toy itself looking like one of those Rubik's Magic Star toys but far more advanced. Calling on the user's to deconstruct it's pattern and reassemble it correctly to solve. Only for the device to contort in to a completely new shape.

On that note, something similar for Mining would be nice to stave off skill decay on miners who have dug all the deeps.