My father-in-law loved crossword puzzle. He would finish the crossword of the daily newspaper in less than 30 minutes. He was 80 at the time. He said that the crossword puzzle is his way of challenging his mind so it would not stagnate and grow old. When the mind is idle then it might atrophy like a muscle that is not used. It may not be a good advice but some old people I know are playing mahjong or betting on horse races. It's not really the gambling but the thrill of winning. And connected to winning is the way to win so it is a challenge to the brain to think of a way to win.
Morning Corie... I wouldn't gamble but I do agree about keeping your mind active and sharp. I've always been keen on Crosswords...especially cryptic ones..although I don't get so much time these days as I used to for them, plus I don't buy newspapers, but I'll complete one if I find any lying around...I also like to play Brain games and mind puzzles online, usually I'll play some kind of puzzle game at least once a day , just to keep my mind sharp!
My life is motivated by curiosity and that keeps my mind active all the time sometimes I will get up in the middle of the night with a project in my mind and I have to put it on paper before I can go back to sleep. This has been why I studied psychology NLP and related subjects. Another thing that motivated me is when a person says [you cannot do that] I usually go out of my way to do it. We live in a country that if you can afford it you put iron bars on the window. The man who makes his living putting bars on window told me you cannot take them down I told him that I want to be able to take them off and paint them and put them back on. He told me you cannot so took me about an hour to explain to him how to do it.
So true what your father-in-law is doing to stay in tip top shape brain wise! My Mom who just made 90 last month reads and reads all day and night. She is sharp, just that her heart is not doing a good job now and she has a pace maker. Staying sharp is very good at all ages too. Fruit drinks helps stay sharp too like no sugar added dark colored grape juice that's all fruit juice. We drink orange juice and pomegranate juice when we can afford it too to keep the heart healthy too. Staying alert and sharp all throughout life is something to strive for always, thanks!