Two 30 foot ropes
blindfold
items to pick up
bag

Draw a 3 foot circle on the ground.
Tie a tautline hitch or small bowline in the end of each rope.
Scatter an assortment of objects around the circle, up to 25 feet away.
An "operator" and a "robot" enter the circle.
The "robot" has a rope tied around each arm at the shoulder, is blindfolded, and carries a bag.
The "operator" holds the ropes and can not speak.

On 'GO', the robot walks forward.
Whenever there is slack in the rope, the robot should walk.
The operator controls the distance the robot walks and tugs on the left or right rope to have him move in that direction.
When moving either left or right, a tug on the opposite rope should stop the robot.
A double-tug on both ropes tells the robot to reach down and pick up an object and put it in the bag.
When the robot has all items, the operator reels it back in.

Time each pair, if you want a competition.
You may also have two operators, one on each rope.