Balloons.
Choose four teams, with two on each team. Each couple is given a toy balloon, the kind that is blown up by the leader beforehand, with a rubber band attached to keep the air in. At a signal from the leader partners link arms and, with their free hands, start batting the balloons down the length of the room and return, using the open hand in batting.
No matter what happens to the balloon they are to keep their arms linked. A balloon is so very dependable in its actions that it is a simple matter for two people of different minds to make it take a straight and narrow path!