It's home made, but I'm really bad about not having a recipe, per se. I just make a white sauce (melted butter, flour, milk, garlic salt, pepper, bay leaf), let it simmer, add cheese, sometimes an egg, sometimes sour cream, stir it in with the noodles. Ideally, I bake it in a casserole with buttered bread crumbs on top, but most of the time it just gets served that way. You can also add veggies to it (onions, but DH hates that, or broccoli) or chicken if you eat meat. To freeze it you can leave it in a casserole dish and cover, so it's super easy to bake. I've been just putting all my freezer meals in gallon-size bags though, laying them flat to freeze, then standing them upright like a filing drawer of food in my freezer.
Here - this is really similar to what I do: http://thepioneerwoman.com/cooking/2009/04/macaroni-cheese/. Probably better, though, because, well, it's the Pioneer Woman.
I've also wanted to try this one, sans bacon: http://thepioneerwoman.com/cooking/2009/12/fancy-macaroni/ Dh hates onions in his m&c, though.
ETA: Also in my freezer: tons and tons of lasagna rolls. Instead of using all my baking pans freezing lasagna, I took the noodles, spread a cream cheese/ricotta/spinach mixture over them, rolled them up, and froze them individually. When we want to eat them, I pull them out of the bag, slop some jarred marinara sauce on them, and bake. The kids ADORE these.