Pop the popcorn. Combine the margarine and marshmallows in a saucepan over medium heat.  Stir until melted.  Pour in the jello and stir well.  Bring it to a boil.  Butter your hands well.  Pour jello mixture over the popped corn and form into balls.  Wrap in plastic wrap.  Orange ones are good for Halloween.  I like to make red and green ones at Christmas time.  The kids love them.  Fast and easy to make.