A couple of years ago I received a Christmas gift from a student of mine. It was one of those desk calendars where you remove a page a day. This one in particular was titles Brain Games. It has a bunch of different types of puzzles in it that are supposed to be done fairly quickly. I tried to start my day doing a few of them in the morning before the day started and found a few of the puzzles quite interesting. One morning , one of the many students in the my class came to ask me a question and saw that I was working on a sudoku puzzle and asked if they could help. Since I was pretty busy anyway, I told them to finish it for me. Well then it began, I didn't know it at the time but giving that student the puzzle lead to a fun part of the class that encourages problem solving and logical thinking. When that student went back to finish the puzzle it lead to about 5 more students asking if they can do a sudoku as well. I showed them the calendar and said I only had the one copy but I would find some more and hand them out later. The next day when I got to school I went and photocopied the next puzzle which was a Binary puzzle. I put them on the students desks and told them to try this one while I take attendance. I was expecting students to finish within ten minutes and then we would move on with the day. They stayed focused on the puzzle for about 45 minutes, coming up to ask me if the answer was correct and then going back to review and find the errors to try again. I was amazed at how focused they were and how they were used some basic problem solving strategies to try to solve it. On that day, nobody solved the puzzle and we had to move on to another commitment.