Ingredients:
2 cups dry macaroni
1/2 cup mayonnaise
2 tablespoons white vinegar
Optional: 1/2 teaspoon sugar (only if you want to cut the bitterness of the vinegar)
Salt & pepper, to taste
1/2 cup celery, chopped
1/3 cup red onion, thinly sliced

Directions:
Cook macaroni according to package instructions. In a small bowl, combine mayonnaise, vinegar, and optional sugar. Season with salt and pepper, and set aside. Once macaroni is cooked, drain and let cool (or rinse under cold water to quick-cool). In a medium bowl, add macaroni, mayonnaise mixture, celery, and red onion, and mix to combine.