Last week, the LIRR had a problem and we were forced to disembark at the Farmingdale station and take busses to points east. While on the bus, I saw this guy working on a puzzle in his copy of the New York Post. Watching over his shoulder, I got completely addicted to this new kind of puzzle - Su Doku. Su Doku puzzles are number puzzles that have to do with placement of numerical digits within a grid. I find them to be the perfect brain-teaser. I've been doing puzzles on the train on my way to work and am finding that they're the perfect brain warmup for the tasks ahead at Underscore.
The only unfortunate thing is that I've been buying copies of the trashy Post to get my daily fix. But I'm going to order a copy of a book from Amazon soon so I can take a bunch of puzzles with me on the train.
Here's a link to a guy's website that contains a nice strategy guide and puzzle generator.