One problem with our society seems to be a mistaken view of old age. In our concern for people who suffer with disease or dementia, we have assumed that all of us are destined for the mental wastebasket. Get over that idea. There are many people in your circle of acquaintances that are old but still mentally alert. They will benefit from activities that are challenging and exciting.
Include your older family members in games, discussions, and activities that give them stimulation. They will benefit from it and you will learn from them.