At home, combine the first 9 ingredients in a heavy-duty, zip-top plastic bag, and seal. Place the corn, shrimp, and couscous in separate heavy-duty zip-top plastic bags, and seal bags. Place the shrimp in cooler.
At campsite, place lime mixture, corn, and shrimp in foil oven bag. Place directly on hot coals (or in a 450° oven if at home); cook 10 minutes. Serve over couscous.