If they are not down for zip-lining, then I don`t know....
In Nayon, in the adventure park, theres is many things you can do for fun: Paintball, rent quads or motorbikes and go crazy or just opt for classic zip-linging.
The canyon you have to cross is quite impressive and the provided view is stunning. Therefore, even though they are still improving the place, defenitely recommendable!
If you are not the type for doing zip-linging or you are the one that is watching the stuff of the group, there is enough possibilities to sweeten you stay as well :)