I would recommend SudokuGeek to any person who enjoys solitaire, and wants to grow the power of their mind.


SudokuGeek definitely fits this bill, and provides multiple levels of difficulty to fit even the newest of beginners, and hard core players alike.

Read 3. Mental stimulation
http://www.mindpowernews.com/ProvenBrainPower.htm

Read this article;
http://www.onlinecollege.org/2010/02/07/your-brain-on-sudoku/