John Medina, a geek on brains, gives 12 rules for using your brain (for example, "exercise"). Some snippets:
"Millions of years ago, if we sat on our behinds for even a few minutes, we could be somebody's lunch." "Active people have half the risk of Alzheimer's of sedentary people." "Any experience you have creates new wiring in the brain." "You make three times more errors on a task when interrupted." "When [the rats] were woken during REM sleep, they had to relearn the maze in the morning."