Arnold Kim, writing for MacRumors:
Some iOS 6 users who use Apple’s scheduled “Do Not Disturb” feature may find that their iPhone, iPad or iPod touch hasn’t automatically disabled the feature on New Year’s morning.
The issue was reported on Whirlpool forums as well as our own MacRumors forums. The “Do Not Disturb” feature silences calls, alerts and notifications when it is enabled. Users may optionally schedule “Do Not Disturb” to activate between specific hours. This allows you to automatically disable calls and notifications while you sleep.
I can confirm being one of the users affected by this bug. As of this writing, it’s 8:46am PST and Do Not Disturb is still enabled on my 4S. I have the feature set from 10pm to 7am daily, so it should be off by now. Before today, DND worked automatically as expected, yet now it isn’t.
Update: It's now 9:50am and it seems the bug's been squashed. My iPhone's now showing this: