In a hope to foster their students' autonomy, capability of decision-making and problem-solving, and thus better equipping them for facing real-world challenges in later life, an increasing number of German schools have implemented so-called 'challenges'. In these novel de-schooling projects, students get the chance to spend a longer period of time, usually two weeks, on a task of their own choice--most often trips by foot or bike over large distances and with limited money. This study explores students' reports of their learning experience and benefits of participation, and the effects of various programme features. 763 students from 13 secondary schools took part in this first cross-sectional exploration of this new phenomenon. Voluntariness and the team aspect of the challenges showed to be the most central factors for students feeling they benefited from the experience. The results suggest that such extracurricular activities may benefit from less regulation by the school.