I don't know what you fellows have in england in the early years of school, but we had school lunches populated with these ketchup packets and these tiny milk cartons. The milk cartons can be turned into a lethally scary weapon very easily as well. If you drink all the milk, and carefully fold down the cathedral top so that it is inverted *into* the carton and place it on the floor... at that point you have a fairly rigid and airtight container that when you stomp on it with sufficient force, it yields an explosion louder than most fireworks. Very effective if you can manage it under a cafeteria table.

On the other hand, I recall puting ketchup packets *inside* the carton and this did not work so well. :-p

Calvin