Grilling - Part 2 - Marinades

Now for those tasty, tenderizing marinades. 
There are usually 2 reasons you use a marinade.  One is to add flavor and the other is to tenderize.  When marinating, it's important to know your beef cut and to plan ahead.  While the two different types of marinades may contain similar ingredients, the key is the length of marinating time.
If you're just looking to add flavor to a tender steak like T-Bone or Ribeye, you only need to marinate for 15 minutes to 2 hours.  Whereas cuts like Top Round or Skirt steaks really benefit from a tenderizing marinade.  The key to tenderizing these cuts of beef is time and ingredients.  You'll want to marinate your steak for 6 - 24 hours.  A tenderizing marinade must contain an acidic ingredient such as lemon juice, vinegar, wine or natural tenderizing enzymes that can be found in papaya, ginger, kiwi, pineapple and figs.  Now for the marinades.
When making, allow 1/3 to 1/2 cup of marinade for every pound of beef.  
If you want to use some of your marinade as a baste or sauce, reserve a portion of it before adding it to your beef.  Marinade that has come into contact with uncooked meat must be brought to a full rolling boil for at least one minute if you plan to use it as a baste.
Again, these recipes are for beef but there are several that I think would be great on chicken or pork.
Balsamic-Mustard Marinade2/3 cup prepared balsamic vinaigrette2 Tbsp. Dijon style mustard
Argentinean Steak Marinade1/2 cup finely chopped onion1/3 cup spicy steak sauce4 cloves garlic, minced4 tsp. dried oregano leaves
Line-Jalapeno Marinade1/2 cup red currant jelly, warmed1/2 cup fresh lime juice1/2 cup chopped, seeded jalapeno peppers2 Tbsp. chopped fresh cilantro1 tsp. salt1 clove garlic, minced1/4 tsp. ground allspice
Ginger-Soy Marinade1/3 cup soy sauce2 Tbsp. fresh lemon juice2 Tbsp. honey1 Tbsp. minced garlic2 tsp. minced fresh ginger1 tsp. freshly grated lemon peel
Red Wine-Herb Marinade1/4 cup red wine vinegar1/4 cup water2 Tbsp. olive oil2 cloves garlic, minced1 Tbsp. chopped fresh thyme or 1 tsp. dried thyme leaves, crushed1/2 tsp. crushed red pepper
Simple Southwest Marinade1/2 cup Italian dressing1/4 cup fresh lime juice1 Tbsp. honey 1/2 tsp. ground cumin
Chili-Cilantro Marinade2/3 cup prepared Italian dressing2 Tbsp. coarsely chopped fresh cilantro1 Tbsp. chili powder
Orange-Cumin Marinade1/2 cup lime juice1/2 cup orange juice1 tsp. ground cumin1 tsp. minced garlic1/2 tsp. salt1/2 tsp. chili powder

Place all of the ingredients for your choice of marinade in a food-safe plastic bag along with your steaks and refrigerate.