The Ground Course
The ground track is a cooperative exercise where you, as a group, try to make your way on wires between the trees. It's hard to explain the joy of balancing forward, but everyone gets totally engrossed in doing it together.
In short, a fantastic team building activity suitable for both colleagues and groups of friends. Suitable for groups with a reasonably good physique.
Can be done as a separate activity, or can be combined with a high-altitude course. Allow 1 hour for the activity.