Possible Clues:

• Last week holiday, briefly
• Regularly appearing, exam days when school's out
• Kiss while holding mistletoe, only the first time it happens?
• Ten minutes since the present time
• Bit of muck in instrument held up brief celebration
• Huge mall event, for short
• Holiday time, in ads
• Advertiser's Yule
• Short winter day?
• "Do not open till ___"