While McDonald's has more than 100 items on its menu, In-N-Out keeps it short and sweet with less than 15 choices. The most popular is a Double-Double burger (two patties, two slices of American cheese and all the fixins').
You can order a straight-up burger with no customization, but much of the chain's cult following swears by the so-called "Not-So-Secret Menu." These are special preparation requests that don't appear on in-store menu boards, but are so widely known, they're even listed on the company's website.
Tops is ordering your burger "Animal Style," which specifies a mustard-fried patty, and in addition to the usual lettuce and tomato, adds pickles, grilled onions and extra Thousand Island-type spread. For monster appetites, there are 3X3s and 4X4s — triple- and quadruple-patty burgers, respectively.
Watching your waistline? Go for a "Protein Style" burger (wrapped in lettuce rather than served on a bun), or eschew meat all together with a "Grilled Cheese."