regular exercise, walking, solving puzzles and eating lots of fish and seafood..........you will never come across senile status.
http://www.funny-games.biz/puzzle-games.html Plus regular sleep, eating healthy food and doing some exercise.
'Actually watching lots of porn keeps one's mind sharp and tool enhanced.' actually it leads to impotency...........you get a hard on but sex does not happen..........end result, brain gets trained to not indulge into sex after hard on and soon does not even get a hard on.
wow thats a cultured bunch. what ever happened to learning a real music instrument? (with some *real* music ... a la Bach, Mozart, Beethoven, Scriabin, etc) I'd recommend for everyone here to go out and buy some textbooks on economics and read those in your spare time.
Learning something completely different....languages, new types of music, probably any new experiences....?yoga