I make a kickass mac 'n' cheese! My circle of friends does potluck once or twice a month, and they're always asking for me to bring mac 'n' cheese. We just had one on Monday and I have the leftovers in the fridge! It's a simple recipe, the secret is lots and lots of cheese, several different kinds.
Make a regular white sauce (melt 2 tbsp butter, stir in flour until it's really thick, then slowly whisk in about a cup of milk and thicken until it makes a smooth sauce), then melt in about a pound of shredded cheese. Okay, a pound might be too much, but a lot. Add milk as needed to keep it from getting too thick. Chop onions. Mix cooked pasta with onions and cheese sauce. Top with a lot more shredded cheese, some parmesan, and a dusting of bread crumbs. Bake at 350 for 30-40 minutes, depending on size, until crispy, crackly, slightly brown on top. Mmmmm.
The key to this recipe is to make the cheese sauce not too thick and not too thin. It needs to be thin enough to be able to mix thoroughly with the pasta and also to give it some moisture so it doesn't dry out in the oven. But it can't be so thin that it pools to the bottom of the dish. Also, I use whole wheat flour and pasta and it works fine.