BS”D
Thanksgiving is defined by always being the last Thursday of November. Never mind all the other aspects of the holiday, the fact that it falls on Thursday implies a very mysterious connection to Kabbalah.
Each day of the week is associate with one of the 7 Kabbalistic emotive attributes (corresponding to the 7 planets, 7 limbs of the body, 7 days of the week, etc.) The Kabbalistic attribute (Sefirah) corresponding to Thursday is “Hod” (in English “Splendor”). “Hod” is root of the word “Hoda’ah” which means “Thanksgiving”, it implies the emotive attribute of thanksgiving to G-d for His goodness.
It is also interesting that on Thanksgiving we eat Turkey – the Hebrew term for Turkey is “Hodu” which also means “to give thanks”. Now, where this connection came from I have no idea – it seems like the holiday of Thanksgiving came about as a manifestation of changing (evolving) kabbalistic dimensions in the universes. “Hodu” is also the very first word of the Shcharit – morning prayer service. It is the beginning of revelation, hence the association with the word “Splendor”.
There is a lot to be said about the Sefirot, and relating to such abstract concepts is difficult for the uninitiated, but through the sefirot the kabbalists can perceive patterns in creation otherwise obscured and concealed to us. There is definitely something special about today then, and as its name applies – it’s about giving thanks (and acknowledgement) to G-d.
Here’s an old post where I talk about the specific level of Hod as pertaining to the coming of Moshiach and revelation of the secrets of the Torah.
http://ronnierendel.com/2009/09/08/the-year-5770-a-year-of-prophecy-and-redemption-2/
Beyond thanksgiving, Hod also has a meaning of “admitting to something that is beyond comprehension”. In the Talmud, the Sages are said to be “modim to Rabbi Meir” – “admitting (from the root “Hod”) to Rabbi Meir – meaning their admit that what he said was right even though they do not understand it on their level. That is specifically a point of revelation – a function of the nullification coming from giving over the intellect for the Supra-rational.