Possible Clues:

• Summer Olympics usually take place in one
• Time a proposal might generate a jumpy listener?
• It lasts 366 days
• 2020, for example?
• Player unhappy about each period of extra time
• 24-hour extension period?
• Many a presidential election occurs in one
• Springtime — when women propose to break with tradition
• 12 months containing February 29
• 'When it's bound to be one in four (4,4)'