How to find the best brain games and puzzles for your personality

There's an awful lot of discussion out there among doctors, scientists and other people in white coats as to the effect of brain-stimulating activity on things like senility and Alzheimer's. Unfortunately, all that discussion isn't producing any real answers--not yet, anyway. But you don't have to wait around for the jury to return a verdict on whether stimulating mental activities can keep your mind sharp.