Sudoko

Apparently this is the newest fad -- its been going on for months in European newspapers, for years in Japan -- but I just heard about it so it is new to me!
Anyway, the aim in a Sudoko puzzle is to fill in the blanks with numbers. Each square must contain each of the numbers 1 to 9, and each row and each column of the whole puzzle also contain each the numbers 1 to 9. Its a logic game, not a math game. Here's an example of a typical Sudoko puzzle:

Above is a typical Sudoko puzzle -- click here for the solution. For background on the game and the fad, see the Wikipedia article here. And for a web-version of Sudoko, here is a webpage where anyone can play.