Here is one of my favorites: your favorite salsa,1/4C vegetable oil, divided; 2T chopped fresh cilantro, 1T chili powder, 2 large finely chopped garlic cloves, 1/2t ground cumin, 1/2t salt, 1 pound sirloin steak, cut into 2 inch strips, 1C (1 small) red bell pepper strips, 1C (1 small) green bell pepper strips, 1C (1 small) sliced onion; flour tortillas, warmed, sour cream (optional)
Combine salsa, 2T oil, cilantro, chili powder, garlic, cumin and salt in large bowl. Add beef; cover. Marinate in refrigerator for at least 1 hour.
When meat has marinated, heat remaining vegetable oil in large skillet over medium-high heat. Add bell peppers and onion; cook for 5 to 6 minutes or until onions are slightly golden and peppers are tender. Add beef mixture; cook, stirring occasionally, for 7 to 8 minutes or until meat is no longer pink.
Serve in tortillas; top with sour cream if desired.