Trying to think of an idea similar to something like Galaxy Trucker where you build up something, it breaks down or gets destroyed and then you try to repair/build it again. Some ideas I'm not completely satisfied with.
-Starfish arms
-City/buildings under siege
Mechanically, the idea is players will be drafting tiles and trying to create sets but players will have to discard some of the tiles during the game. Discards will occur randomly during the game, not by other players, but by two or three random events that you will have some control over as far as defense.