I think it would be cool to make a pretend RTS game, where you require buildings to craft certain things or store items. You'd start out with around 5 troops, have them gather wood and dirt. Build a small dirt-walled structure and put a crafting table inside. Manufacture wooden pickaxe. Assign miner. Return and renovate tools workshop into stone, and manufacture stone tools. And so on. Eventually walls could be built, stuff like that.
tl;dr - Play command and conquer in minecraft.