A young boy and an alien child help an entire planet learn The True Meaning of Christmas™.

A comparatively weak story later lengthened sufficiently to publish as a book with the same title. I actually remember reading it in its original incarnation, but that was largely because of the novelty of having Asimov appear in Boy’s Life, to which I was then a subscriber. Considering the quality of the other sf which appeared in Boy’s Life in the early 1970’s, this story is not at all bad—but it is not top-notch Asimov by any means.