Gothamist loves puzzles. In high school we were one of those kids who sat in the back of the room and did the Times crossword (ok, so that could describe most of our high school, but that's Stuy for you). And so it's no surprise that we've become completely addicted to Su Doku this summer. What does surprise us is that the game seems to be sweeping the nation. According to USA Today (which also publishes the game) Su Doku books are flying off the shelves. Where three weeks ago there were no books on the topic on their book list, now there are six.

The game appears really simple: You get an 81-square grid broken down into nine smaller nine-square grids. Each row, column, and smaller grid must contain the numbers 1-9. That's it. You can find two boards everyday in the Post (plus an additional two Grand Master challenge boards every Sunday and Monday) and one in USA Today, or you can just play the web version here. Not to mention all of the downloadable versions out there.

What do you think of Su Doku? Any good tips or tricks?