Except for the powerful nootropics like modafinil, I doubt you'll see anything but a placebo effect from piracetam and the like.
Research does keep popping up that exercise is the single most powerful thing you can do for your brain.
The mental puzzles can be entertaining. They're probably better for your brain than watching TV. But if you really want to improve your mental abilities, the task has to be almost uncomfortable and repeated for many months. Have you ever learned a new language or how to draw? In the beginning, the training (like intense exercise) makes you question what the heck you're doing, whether it's worth it. Then your brain adapts. That adaptation is the new power you want. You want even more power, you push yourself farther.
The puzzles in their simplicity probably aren't going to teach logic or drive. For logic, you need to read good books, talk to better people, keep yourself emotionally detached, and give yourself time to think about it all. And drive is something that's a combination of emotions, outlook, and physical and mental energy that would be better served by meditiation or by actively immersing yourself in projects and social groups.
Edited by NarrativiumX, 29 December 2008 - 06:34 PM.