There is a new Google Now card for a search on [Let's Go Caroling], honestly, I am surprised it does not work on all Google searches.
In any event, when you search Google Now for [Let's Go Caroling] you get a bunch of different carols to chose from and click on. You also get a bunch of festive people dressed in Google colors singing.
Here is a picture:
Phandroid posted a video of this in action:
Forum discussion at Google+.