Amber Johnson from forwarded me this link that features scientifically proven ways to get smart. It includes watching specific types of TV shows that have many overlapping stories, a large cast, moral and plot ambiguities. More obvious suggestions include: learning a foreign language, sleep, listen to music.
Recommendations such as crossword puzzles, chess, and other memory stretching activities are perhaps also equally beneficial for those fighting to stay lucid in old age.
Some surprising ones: playing video games, riding a motorcycle, benefits of aging (our brains reach peak efficiency around 40?), and transcendental meditation.