The answers to the clues below will have something in common. Can you determine what it is?

1. Irving Berlin classic
2. Color named for a bird
3. Half of a Dr. Seuss classic
4. Prune ancestor
5. Hester Prynne's emblem
6. Metaphor for faith

Answers:

1. "White Christmas"
2. Peacock blue
3. Green eggs
4. Plum
5. Scarlet letter
6. Mustard seed

 What they have in common:

Each answer contains the name of one of the character pieces in the board game CLUE:

1. Mrs. White
2. Mrs. Peacock
3. Mr. Green 
4. Professor Plum
5. Miss Scarlet
6. Colonel Mustard