I am wondering if it would be feasible to include some furniture or features that allowed players to create puzzles on their land.
I'm thinking like teleport pads or doorways activated by codes or something like that.
I realize they'd have to have to be careful with what was allowed, but it would be neat if you could write a clue book (maybe just pics of the objects, so it would be a scavenger hunt) and direct people to certain objects with which they could interact to unlock a puzzle. The ability to load a treasure card into the puzzle as a reward would offer some payoff.