Three Wise Men

Grant Mathews suggests another possibility: alignment of planets:

  Feb. 20, 6 B.C., when Mars, Jupiter and Saturn aligned in the constellation Pisces.
  April 17, 6 B.C., when the sun, Jupiter, the moon and Saturn aligned in the constellation Aries while Venus and Mars were in neighboring constellations.
  June 17, 2 B.C., when Jupiter and Venus were closely aligned in Leo.

The only "publication" I could found: http://www.foxnews.com/story/0,2933,318014,00.html

Another possible interpretation. Unfortunately it's in French http://www.meessen.net/AMeessen/#the_Bethleem_star (pdf)

Abstract: "According to the Bible, wise men came to Jesusalem, to ask were the “King of the Jews” was born, since that seemed to be announced by the appearance of the “star” that they had followed. They found the child in Bethlehem. Chinese records tell us that this could correspond to the comet, which was visible in the year -5."