I was reading the Radiance Sutras last night and found Sutra #50 that totally relates to and celebrates the Spirit of Thanksgiving. I especially recommend considering this Sutra #50 as a Thanksgiving meditation or to read before your Celebratory and Glorifying meal.
Also, I like the word-concept Thanksgiving. Not only does it mean giving thanks but the active verb of giving takes you outside of yourself to connect with the whole of Self.
All the very best,