Barbara Thomson, an Edinburgh primary head seconded to A Curriculum for Excellence, said valuable learning did not need to be in class with a teacher.
Opening the conference, Kevin Brown, director of the Scottish Out of School Hours Learning Network, said it need not even be on the school grounds.
"Recently, we have moved away from it being school-based," he said. "We need to try to do this within a framework, and I think A Curriculum for Excellence could provide that framework."
Almost all secondary and more than three-quarters of primary schools provide out of school hours learning (OSHL) in some form, from breakfast clubs to study support and from Outward Bound to summer schools.
Summer Kenesson, director of the Quality in Education centre at Strathclyde University, which has researched the topic, said it was important to check how OSHL helps learning. Ownership by the children could aid this, for example, creating a journal setting out their understanding of how and what they are learning.
However, Ms Kenesson accepted that a stumbling block to bringing OSHL into the new curriculum was that some children enjoyed having interests and activities independent of school. Her research also found parents remained primarily concerned with attainment and exam performance, rather than the extra-curricular activities available at their child's school.