The brain fitness channel has this good advice for selecting activities that help keep your brain sharp:
1.They should teach you something new. The brain is a learning machine. To keep it strong, you must continually develop new skills.
2. They should be challenging. Activities should command your full and close attention to drive chemical changes in the brain.
3. They should be progressive. You can begin a new activity at an easy level, but continuously challenge yourself to stay on the edge of your performance abilities—at your “threshold”—so that you improve. This goes for old activities you enjoy, too: pushing yourself to improve will help your brain.
4. They should engage your great brain processing systems. Tasks in which you must make fine distinctions about what you hear, see or feel and use that information to achieve complex goals drive the brain to change its abilities on different levels.
5. They should be rewarding. Rewards amplify brain changes, leading to improved learning and memory. They turn up the production of crucial brain chemicals that contribute to learning, memory, and good spirits.
6. They should be novel or surprising. New, positive and surprising experiences exercise the brain machinery that makes you bright and alert.