It's your team Vs their team. Get the ball off of their side of the parachute and keep it from falling off of yours.
Prevent the ball from falling off of your side of the parachute and try to get it to fall off of the other team's side.
Divide the children into two teams (2 halves) around the parachute. Have everyone standing and holding the parachute. On "Go"! the teams will attempt to knock the ball of of their opponents side of the parachute while making sure it does not fall off of their side.