What to do with huge bunches of parsley? You can freeze it, of course - either in ice cube trays or simply chopped and sealed in freezer bags. But one of my favorite things to do is to make Parsley-Mint Pesto. The addition of mint is great but you can skip it if all you have is the parsley.
You can use the pesto on pasta (1 cup for 1 lb cooked pasta), where it is great on its own or with the addition of chopped red pepper, dried tomatoes, and/or shredded chicken. It's also good on pizza with whatever you like, tossed with potatoes, and even with winter squash.
You can make big batches of pesto now (and this goes for basil pesto, too, of course) and freeze it in single-meal quantities. Put 1/2 cup or 1 cup of pesto in a quart freezer bag, flatten it out, and stack them up in the freezer. You can thaw and warm it in a bowl of warm water in about 10 minutes.