Possible Clues:

• Ignore the teleprompter
• Go off-script (sorry, Ella, it doesn't mean 'get more pounds')
• Forgo the cue cards
• Robin Williams forte
• Comment off-the-cuff
• Modern party that's unprepared
• Talk without a script
• Ignore the cue cards, say
• Wing it vocally
• Disorient one's co-stars, in a way