Big Week Out is an annual Christian youth event. Young people, usually in year 8 to 12, along with mostly young adult leaders. Typically about four days, running each day from morning to evening. The focus is putting Christian faith into practice by serving the community and a large part of the time is spent at a variety of community service events. There’s also worship, teaching & discussion, meals, and fun & games.
You could think of it as a typical Christian youth camp, minus staying the night, plus the service events, with the other stuff squeezed into the rest of the time.