Garlic Scapes are basically the flower stalk on a garlic bulb. When growing garlic you cut the flower stalk off so the plant doesn't use the energy to make seeds and you end up with a bigger bulb. You could throw the flower stalk away, or you can use it to cook. I can't say I've ever seen them in the store, but I have seen them in farmers markets and CSAs. They're usually 12-18" and twisted in shape.