Preheat the oven to 425 degrees F. Place six 6-ounce ramekins on a baking sheet.
Bring a large pot of salted water to a boil. Cook the pasta according to the package directions, then drain.
Meanwhile, toss the American cheese and pepper jack in a medium saucepan. Add the evaporated milk and some salt and pepper and cook over medium heat, stirring, until smooth and just bubbling. Add hot sauce and season to taste. Stir the cooked pasta into the cheese sauce to coat and divide the macaroni and cheese evenly among the ramekins. Sprinkle the cracker crumbs on top, then bake until the sauce is bubbling and the crackers are golden brown, about 7 minutes.