If you use Do Not Disturb mode in iOS 6 then you should probably de-activate it until the 7th of January otherwise your Do Not Disturb period is likely to stay on past its scheduled end time according to the Apple Support site.
After January 1st, 2013, Do Not Disturb mode stays on past its scheduled end time.
Do Not Disturb scheduling feature will resume normal functionality after January 7, 2013. Before this date, you should manually turn the Do Not Disturb feature on or off.
To turn off the scheduling feature, tap Settings > Notifications > Do Not Disturb and switch Scheduled to Off.