pop-up ephemera

How's this for a novel advertising gimmick. I discovered this spring-loaded matchbox in my father-in-law's basement where all sorts of wondrous ephemera lurks inside cardboard boxes. It has a hologram of an opening and closing eye on the outside, and when you open the box a pop-up advertisement for a sedative flips up. It's a simple but effective piece of pop-up technology using a piece of elastic to activate the perforated label. I'm gathering little boxes so that I can use this technique in other fun and surprising ways.