If you have living grandparents, spend some time with them.
Of course, there are extenuating circumstances in which one might not appreciate one's grandparents, or in which one's grandparents are monsters not worth appreciating. A harsh reality for some, and that is tragic. If this is not your case, however, then I suggest taking some time out to spend with your grandparents. Don't wait until Grandparents' Day, whenever that is.