Stuffed eggs are always popular. If preparing for a crowd, you might want to triple the number of eggs and make up all three alternative additions.
Slice hard-boiled eggs in half lengthwise. Remove yolks into a bowl and crumble with a fork. Mix dry mustard and vinegar to form a paste, then add to egg yolks along with mayonnaise, salt, and pepper. Add either celery, bacon, or ham. Stir together with a fork and mound into egg whites. If desired, garnish with a little paprika and chopped chives.