Programming course for students

Recently I have accept a challenge from a friend to produce a programming course ware. This might sound easy from the first tought. Afterall, you can just pick a programming book from the shelf and see what they have in their contents. But not quite for this case. There are quite a few constraint factor that need to be considered :

1) The target audience is secondary school student who is the the age range between 14 to 17.
2) The course is only 32 hours. To divide the time between theory and tutorial, it is about 18 to 14. Meaning 18 hours of theory and 14 hours of tutorial.

There is nothing much that you can teach about programming in 18 hours, so we have to really squeech the contents but the integrity need to be maintained.

To keep the students sustain through the course, the contents have to be interesting enough such that they will produce a useful program at the end of it.

Looking at the age group, the course cannot cover very indepth topics likes OO, algorithm and advance data structure. If you take these 3 topics out, it doesn't leave you with much option as to what program you want them to write at the end.

Currently, I am thinking of a calculator program. Calculator is just nice to cover the basic programming elements.

If you have any other ideas, please let me know.