Last year my kids received a Nintendo DS for Christmas and my wife purchased Brain Age: Train Your Brain in Minutes a Day! We both really enjoyed the challenge and the kids were actually pretty good at it too. The other day I stumbled upon a website that provides similar (and probably better) brain training. The site is Lumosity and it is a great collection of brain training and grain games that can lead to:
Clearer and quicker thinking
Improved memory for names, numbers, directions, etc.
Increased alertness and awareness
Better concentration at work or while driving
Right now they are offering a free 7 day trial of their subscription service. I highly recommend checking it out.