Interesting. Very interesting. Richard Restak gives this is a series of 28 steps that one can take to actively enhance ones brain. It's a good quick, but useful read if you get the time. Very approachable. Of particular interest to me were the discussions on metacognition, memory, learning through old age, and brain cell behavior through old age. I'll list the 28 core points.

1. Learn about your brain
2. Apply your knowledge of the brain to organize your ideas
3. think of the brain as a montage engine
4. learning capacity stays with age
5. learn & use your motor skill
6. profit from the link between learning, memory, and intelligence.
7. Improve your memory
8. Develop emotional memory
9. Think in terms of brain geography
10. Develop linkages
11. Do things that stimulate lots of the brain
12. let the brain be the brain
13. practice forms of mental hygiene
14. use emotions to advantage
15. reduce stress
16. harmonize with body rhythms
17. concentrate
18. train in logic
19. develop a tolerance for uncertainty
20. meta-cogitate
21. read widely
22. heighten your senses
23. experience art & music
24. exercise
25. use your hands
26. relaxation exercises
27. use technology ;)
28. act in harmony with your talents