>Or just go buy Microsoft Money or Quicken.

Then do the homework on them: find out where they do wrong, why, and how would you do that better.

Not that I expect the beginner to actually do one better, but rather to start thinking about the interface.

Actually, this checkbook app is something I've seen done several times by several people who, well, tried. Not that any of them became programmers (nor was anything they wrote usable by anyone but themselves - but it worked :), but they became power users and actually helped propagate the IT thing in places where they worked. In the end, they learned a lot and were able to help later.