Hanukkah is about the Temple. It happened about 2100 years ago, during the reign of King Antiochus IV. He didn't like the ways the Jews worshipped, and started to order that they convert to Greek costumes, and order the desecration of the temple by placing idols within the temple walls. A small group of Jews, called the Maccabees, fought back, and against all odds beat the Greek legions. When the Maccabees reclaimed the temple, and went to rededicate it, they could only find enough oil to burn for one day. Miraculously, that oil burned for 8 days, until more oil could be procured, and the temple rededicated.
In my opinion, this miracle is well worth celebrating, regardless of religion. The bible indicates that Christ celebrated Hanukkah (John 10). And it was not part of the Law of Moses, so celebrating it is not lessening our respect for the Atonement.
Anyway, Hanukkah and Thanksgiving one the same day, is pretty awesome! Two holidays focused on being grateful, what an neat thing!

