Mac N Cheese Please!

So I plan on baking a macaroni pie this Turkey Day but this is my 1st time. Most people I know have been here and done this, so I'll tell you guys what ingredients I picked up and you can feel free to add anything that you deem necessary. I picked up elbow pasta (of course), sharp cheddar and mozerella cheese and carnation milk. I've also heard that I could add eggs and chopped onions, so I'll incorporate those things. I suppose it sounds simple enough and I'm a great cook so I'm sure it'll be tasty. Baked macaroni is one of my favortie foods so I figured I should try making it for a change. As I said, feel free to let me know how to jazz it up!