This website is more like a whole group of ´ungdomsskoler´
http://www.randersungdomsskole.dk/asp/index.asp
The teaching is mostly hobby-related, but there are languages like Spanish that would not be available at the local Folkeskole, and classes for scooter driving licences etc.
Serious knowledge and skills are taught, and there is a full-time school for young people with special needs.
It is not a boarding school at all, though some courses may involve travel and staying overnight over a weekend or for a few days.
It should not be confused with an ´Efterskole´ either.
My son dabbled with computers (but preferred his own at home) and tried out snapping and developing his own black-and-white photos at our local department some 10-15 years ago. I still treasure some of those photos!
But that was called a Juniorklub.
I'm not sure what you would call it - a special youth version of the Danish ´Folk High Schools´ - which are not ordinary high schools either...