Remove husks from fresh ears of corn if using; scrub with a stiff brush to remove silks and rinse. Cut kernels from cob. Cook kernels, covered, in a small amount of boiling salted water for 4 minutes. (Or cook frozen corn according to package directions.) Drain corn. Transfer corn to a medium bowl; stir in carrot, green onions, and sweet pepper. Set aside.
In a small saucepan, combine sugar, vinegar, salt, celery seeds, dry mustard and hot pepper sauce. Bring to boiling; reduce heat. Simmer, uncovered, for 2 minutes. Carefully pour sugar mixture over corn mixture. Let cool slightly. Cover and chill for at least 4 hours or up to 2 weeks. Serve with a slotted spoon, if you like with pork, beef or poultry. Makes about 3 cup (12, 1/4-cup servings).