There is no one magic bullet that is best (either crosswords puzzles, or computer-based programs, or physical exercise):SMART X  we do need a variety of mental stimulation or "brain exercises"."Cells that fire together wire together" means that synapses-unions between neurons- get solidified the more often the respective neurons "talk" to each other.Dana Press kindly sent us a couple of books. One of them, The Dana Guide to Brain…