I'm getting all disappointed in this thread. It started off as a way to shjooshh up mediocre ingredients and has descended into "what is the most obvious dish to make with this?"
If your popcorn is salted/neutral, Dani - I suggest something a bit interesting; much like crushed-to-death Cornflakes, smashed Popcorn make amazingly good "breadcrumbs" when applied to chicken fillets! They add a unique flavour and texture indeed. Use a thin film of beaten egg, make sure they are VERY finely smashed, then apply egg then popcorn to each fillet before cooking!!
MY INGREDIENT IS: FRESH HORSERADISH!