The two of my daughters that are still at home made breakfast for lunch after church for my daddy (their G'Pa) and his gf, who are very devoted, doting grandparents. I know they planned it at least a week ahead of time, because they invited them a week ahead of time. All day Saturday I wondered why they were so intent on getting the house cleaned up, and hollered at ME when I left something sitting out! I'm really proud of them because I completely and totally forgot about it.
They probably heard about it and got reminders from school or church (or both) :)