Possible Clues:

• It was given to Regis Philbin
• 'Who Wants to Be a Millionaire' catchphrase
• 'Is that your __?': 'Who Wants to Be a Millionaire?' inquiry
• "Is that your __?": "Who Wants to Be a Millionaire?" inquiry
• Certain game-show contestant's response
• Regis Philbin asked for it
• Famous game show query