If you're at work and counting down the days to Christmas, you should try tuning in to the online radio station Merry Christmas Radio. Don't let the somewhat cheesey name fool you: This really is a hip holiday station, playing everything from old standards to rock-and-roll renditions of the classics.
To listen, you can either open the radio player in your browser window or download the file to stream through your iTunes. Just be warned: Because the radio station is free (yay!), it isn't always available at peak hours. If too many "free accounts" are using the service, just check back later. (This happened to me earlier today, but now it's working fine.)