Cut broccoli into bite-size pieces. Cut onion into broccoli. Add raisins. Fry bacon until crisp; drain on paper towel and tear into small pieces. Mix broccoli, onion, raisins, and bacon together.
Combine mayonnaise, sugar, and vinegar and pour over broccoli mixture. Stir well and chill until served. Serves eight.
Note: This recipe can be easily increased for larger crowds.