There are a couple of popular signs for "Thanksgiving."
A common method is to move a right Q-hand from the chin to the chest.
Thanksgiving: (Version 1)
Another popular method of signing "Thanksgiving" is to do a "double handed" "double-arching" version of the sign "THANK-YOU."
Thanksgiving: (Version 2)
Animation: Thanksgiving (version)
Also see: TURKEY
Notes: