Examples:

• Oh, the million dollar question. What goes on inside others' heads.
• Well, that's the million dollar question, right?
• That is the million dollar question isn't it?
• Well, that's the that's the million dollar question.
• That's the 250 million dollar question.
• The million dollar question is, do you know what you're doing?
• Huh, that's the million dollar question, isn't it?
• The million dollar question is, do you know what you're doing?
• Its really literally it is a million dollar question.
• That's the million dollar question.