Thanksgiving or Thanksgiving day, “presently celebrated on the fourth Thursday in November, has been an annual tradition in the United States since 1863. It did not become a federal holiday until 1941. Thanksgiving was historically a religious observation to give thanks to God, but it is now considered a secular holiday as well. Most people celebrate by gathering at home with family or friends for a holiday feast. Though the holiday’s origins can be traced to harvest festivals which have been celebrated in many cultures since ancient times, the American holiday is tied to the deliverance of the English settlers by Native Americans after the harsh winter at Plymouth, Massachusetts and that event has become the pre-eminent foundation story for English North America.” (Wikipedia)

There are so many different lessons and projects that can be done in the classroom (or at home) for the Thanksgiving holiday. There is a list of some ideas (for grades K-3):
Art Projects:
Turkey Hand Puppet from a Plastic Glove
Handprint Turkeys for bulletin boards or to take home
Lessons:
Graphing Favorite Thanksgiving foods
*All of these activites and lessons can be found on The Lesson Plan Page