Back when my oldest was 3 yo we had some friends over one night. My wife's birthday was coming up, so to keep my daughter busy I told her to make Mommy a birthday card out of construction paper. My daughter finished the card and "hid" it right behind the recliner on the floor.
I told her that Mommy will see it back there. She told me, and our guests, that it was good hiding place because Mommy never cleans back there.
I still kid my wife about that one.