I have to teach Java programming to school students and all are around the age of 15. None of them had any previous experience in programming. That is, I have to start from the very basics. I do like to make the sessions more interesting, and to make them love programming. I do need simple problems or puzzles -- not complex ones, simple ones -- that can increase their curiosity, and made them think and love programming. I do like to have problems for all of the concepts (like branching, looping, encapsulation, inheritance, composition, etc.,). Notes: I do have a time-frame of 1 hour for each session. Computers are not available. Maybe I can bring my laptop and show a demo to them. There are 7 students in the class.