Related Clues:

• See 21
• The reverse of formal wear
• The reverse of shadows
• Leaders may be called ahead of the 10
• Obverse result of coin-tossing
• Obverse of a coin
• Coin toss option
• Top hat accompaniment
• Spies on, in a way
• Toss option
• "Tails" alternative
• Overzealous promgoer's choice, maybe
• Some calls before a football game
• About 50% of calls
• Something with a 50-50 chance of appearing