Leftover parmesan rinds are actually pretty useful in the kitchen, including making a tasty, crunchy snack with just a microwave. This video explains how it's done.
Cut your rind into bite-sized squares, space them out on a microwave safe plate, and microwave them for 30 seconds. If they're not crispy enough for you, pop them in for up to 30 more seconds, but keep an eye out so they don't overcook. In a snap you've got delicious, crunchy cheese crisps that are perfect for snacking or tossing onto a salad.
How to Make Cheese Crisps Like Richard Blais [Food & Wine (YouTube)]