The most popular course in Rjukan (and actually in Europe) is the Beginners Ice Climbing course.
As the name sounds, it's for total beginners. What that means in practice is usually about half of the twelve participants have never been rock climbing, and the other half have some experience top-rope climbing or leading. With two instructors, the split works well and we can move about from climbs that are just a little steeper than walking, up to vertical and even overhanging mixed routes if your heart desires.
If you're interested in one of these beginners courses, google "Skyhook Adventure" or head to skyhookadventure.com