sudoku, a new obsession

Last night, after a dozen cups of coffee/espresso drink, and group dinner, it was difficult to fall asleep when I returned to the hotel at 10:30pm thursday night, so I started browsing through newspaper and saw sudoku puzzle section. I saw sudoku books, a small pamphlet-like pocketbook , at the local bookstore so I was somewhat familiar w/ it, and dismissed it to be yet another puzzle.

Since I couldn't sleep and didn't dare to have TV on to wake up other people at the hotel, I picked up the pencil by bed-stand, and got started on it. The rules were simple,
1st: there are 9x9 slot table where numbers 1-9 must be unique in each row, each column
2nd: also 9x9 is divided into 9 3x3 tables and the numbers 1-9 must be unique in each of these tables.

There are a few numbers pre-filled, and I have to try inserting different numbers within the above 2 rules. As the description below rules say it's simple and logical approach, and I wrote down unclaimed numbers in margin, compare to the rest of rows/columns it occupies. First 2 rows&columns I've completed seem fairly straight-forward. After completing 3 rows and 2 columns, I found out that top middle 3x3 box-set can only take '5' and '8', and found out that I'd end up w/ 2 '5's in that column, the 6th column in 9x9 table. I either had to start all over or give up. I gave up.

It was pretty intriguing and while eating breakfast I found myself scanning for sudoku on morning newspaper.

Not sure what Sudoku means, but it's fairly addictive.
Hope I pay more attention to the conference presentations than to sudoku during day time today.
:)