So-called variety meats, or offal, are the various pieces of a meat animal that aren't made of straightforward muscle. Even intestines are used in many traditional dishes, such as Mexico's rustic "tacos de tripas." The tripas, or beef intestines, are usually finished by grilling them over intense heat for a few minutes. This gives them a crispy, well-browned exterior but leaves the inside tender. It's an unusual and tasty taco you won't find in chain restaurants.
Open the package of tripas and slide them out into a large bowl. If they're braided together, separate them with your fingers. Cut the tripas into lengths of approximately 6 inches, using either a sharp knife or kitchen shears. The lengths will resemble extra-long pieces of rigatoni or other tube-shaped pasta.
Rinse the pieces of tripa individually, inside and out. Brands sold in the United States are cleaned thoroughly, but for food safety it's prudent to give them a further cleaning.
Bring a large pot of water to a boil, and add the tripas. Turn the heat down so the pot remains at a bare simmer, and gently cook the tripas until they're soft. This takes about a half-hour.
Drain the tripas thoroughly in a colander. Heat a griddle or heavy skillet to medium-high heat, then add a tablespoon of oil or -- for a more authentic taste -- lard. Cook the tripas in small batches for about 10 minutes, stirring frequently, until the outsides are browned and crisp but the insides are still soft.
Serve on corn tortillas, with guacamole or spicy salsa and your choice of toppings.