I just made the best mac & cheese, from a Jeanne Lemlin cookbook. Basically, you boil 2 cups of elbow macaroni, and meanwhile make a roux: 2 tbsp flour, 2 tbsp melted butter, 2 cups milk, 1/8 tsp dry mustard, a dash of cayenne and a bit of salt. You mix the pasta with the sauce and cook it in a 2-quart container at 400 for 15 minutes. At first, my kids asked, "Is it Kraft?" but then they forgot about that and munched away contentedly.
P.S. I left out the cheese in the list of ingredients. You mix it into the roux: 2 cups cheddar and 1 cup smoked Gouda. The Gouda really makes a difference.