Possible Clues:

• "That's a surprise"
• Noncommittal response
• ''You said what now?''
• Request for repetition
• 'Wow, I didn't expect that!'
• ''Say again?''
• Answer that probably won't earn you any points on a game show unless the prompt is 'This one-syllable sound usually indicates someone doesn't know what you're talking about'
• John Mellencamp "Uh-___"
• ''That's news to me''
• 'Say it again?'