Sudoku

OK, now that you've figured out how long you'll live, what your "Real Age" is, and tried a little hand-eye coordination, it's time to exercise your brain. We know that as we age, as important as it is to keep our bodies fit, it is also important to keep our mind active and engaged, to that end I invite you to try out a Sudoku Puzzle.
Here are a couple links to get you started.

http://sudoku.com.au/ Note you that you can set the level of difficulty.

http://www.sudoku.com/

http://www.dailysudoku.co.uk/sudoku/index.shtml