Logic puzzles

After the initial rush, last night was a little slow at work. My coworker Teri and I like to do crossword puzzles when we have the time. Usually we just pick up whatever Washington Post is lying around and do the puzzle in that one. Tonight the Post had something new to offer. It is a logic puzzle with numbers called Sudoku. There is a 9 box by 9 box grid. There are a few boxes filled in to begin with and then you have to fill in the grid so that every row,every column, and every 3x3 box contains the digits 1 through 9. It is way more challenging than a regular crossword puzzle. I didn't finish mine, but your brain gets kind of fried at 3 am. I'll attack it again after I wake up.