#9: Code Names
It really takes so little to entertain children. Unless you’ve already spoiled them so now they’re not happy unless they are jetting to Aruba on a private plane, they are quite easily pleased with small things, especially if you find a way to turn it into a fun game.
But I bet that what really made this significant to this kid was more than the secretive aspect or the code name or the adventure of it: it’s that she had something special to do with her dad, and her dad clearly wanted to spend time with her. That means a lot to kids.