I also grind whole flax almost every morning and have it on my oatmeal. It's got lots of Omega-3.
I bought and worked through PositScience's auditory training a few years ago, and thought it was really good. (Learned about it through the book The Brain That Changes Itself.)
I get a reasonable amount of exercise - cycle commuting, walking at breaks, and weights at the gym once or twice a week.
I also like to write down lists of things to test my memory - bore, stroke, and displacement of certain engines, manned spaceflight mission details, Stanley Cup winners, math puzzles, etc.
So far it all seems to be working OK, but of course it's not a controlled experiment - how would my couch-potato TV-watching alterego do?