Possible Clues:

• Jokey reply to someone geeking out
• Jokey response to an overly technical explanation
• 'Here comes Poindexter!'
• Teasing words when someone starts listing the digits of pi, say
• Shout after a too-bookish discourse
• "Check out the brain over here!"
• 'Check out the brain over here!'
• "Geek sighting!"
• 'Geek sighting!'
• 'Ha ha, what a dork!'