In what's becoming a U.K. holiday tradition, the BBC is serving up a Doctor Who Advent Calendar counting down the days to the year end (and David Tennant-ending) special, The End of Time.

For the uninitiated, an Advent calendar counts down the days from December 1 to Christmas Day. Kids unveil the dates one day at a time, sometimes revealing little presents to enjoy along the way. In Doctor Who's case, fans receive goodies each day until Tennant's final episodes as The Doctor.

But, since an advent calendar is a Christmas tradition, and three people in Oxfordshire objected to showing any preference to a particular holiday, the BBC quit using the term and changed it to "Adventure Calendar."

Will NBC's 12th annual 'Christmas at Rockefeller Center' special, scheduled for tomorrow night -- with singers and actors prepared to celebrate the lighting of the famed Christmas tree -- go dark?

That's the threat posed by members of National Association of Broadcast Employees and Technicians (NABET-CWA) Local 11, which issued a statement today saying it would halt the show via a wildcat strike if NBC doesn't make progress on stalled negotiations with the union, which has been working without a contract since March.

If the broadcast goes dark, don't blame the union -- blame NBC, says NABET-CWA Local 11 president Ed McEwan in the statement. "We can't let the Grinch at NBC steal another Christmas from thousands of honest working people," McEwan says in the statement. "This charade must stop. Christmas is supposed to be a time of goodwill, but the network's management is trying to hide behind their fancy lights while leaving their employees in the dark."