Bet that subject heading got your attention--what in the world?
When I taught in Vero Beach, Florida a dozen years ago there was a factory about an hour or so north of there--Cocoa Beach maybe--which made football helmets. The punchouts were some of the coolest sponge material I have ever seen. I just did my "snowman" painting with first graders where they stamp/sponge paint the snowman--white tempera on royal blue paper. The second week we add the details--face, hat, who is coming to visit your snowman?--with oil pastels. It's really a favorite lesson.
Anyway--I would love to get more of those punchouts. Does anybody have the name and address of that football helmet factory?