Heard of this word before? Me neither until I read this article on rediff.
I have been seeing Sudoku table in The Times Of India since few days.

So what is Sudoku ?
Sudoku is a number puzzle. Its Originated in Japan. Sudoku consists of a 9x9 grid, further divided into a 3x3 subgrid with a few numbers thrown in. Challenge is to fill each of the blank boxes in the rows, columns and 3x3 squares with digits from one to nine without repeating a single digit.
Sudoku