I love Puzzles, like I love Transformers- they stimulate the mind, give you something to solve, and something to focus different parts of your brain on.
My two current favorites are a tablet game called Block Hexa Puzzle and Microsoft Solitaire Collection with it's five daily challenges. I am currently 5 for 5 every day this month, even on the sadistic and evil "solve this in this number of moves" challenges on free cell.
Be good to your brain- feed it what it needs to work best, and exercise it. Don't face the world with a flabby brain.