Collecting cans of food for the Food Bank can become a weak activity as people get tired of collecting the same old thing. Instead, collect boxes of Kraft Dinner and set them up like dominoes on the gym floor. Have a member of the class that brings in the most Kraft Dinner be the person who knocks over the first Kraft Dinner domino and sets all of the others flying. You can make very interesting patterns with all of the different colours of boxed macaroni. When you are setting up the dominoes, you can take one or two out of a pattern so that a slip of the hand doesn't set the whole display off by mistake.
Make sure that you check with your Food Bank to see if they want to have all of this nutritious mac'n cheese!