Courses and course formats

I'm currently working on a Moodle installation for a primary school with students aged 8 to 13.

What I'd like to do is have plenty of images to brighten up our Moodle and I thought about having a whole load of images as links to other courses. So for example I might have a "Parents' Area" as the main category heading and where "Homework" might normally be a sub-category which is then split into subjects I would have it as a course instead with icons as links to the subjects. The problem with this is that courses ask the user to enrol - obviously I wouldn't want parents to enrol onto the Homework course but rather enrol onto the course for the individual subjects.

Does anyone know whether this is possible? Can you switch off the requirement to enrol in a course? Can a course be treated more as a sub-category?

I would really like to hear from anyone else who has considered this.

Thanks in advance.