Is anyone else addicted to this puzzle? I have only recently discovered it but I am finding it lots of fun. Some of the harder puzzles can be quite fiendish to figure out. I am going to take a book of sudoku puzzles, a pencil and an eraser on our upcoming cruises. I think it will be a great sea day pasttime.

Sudoku site

Basically, you get a 9x9 grid with some numbers in some cells. Each column, row, and 3x3 box must all contain the digits 1 - 9 (there is no room for repetition of a digit). This is not a math project. The numbers are just symbols and only logic is required.