Whenever I'm on the move, I always carry a few sudoku puzzles with me. If I'm waiting for the bus or on something else, I whip out a puzzle and go to work. It's something that is quite simple, (some can be complicated however.) and gives your mind something to focus on when you're bored. I print out th puzzles from this wensite http://www.puzzles.ca/sudoku.html. There are many to choose from, easy, medium and hard., two per page. I hope someone else can enjoy these too!