There are many that have special Thsnksgiving Day menus. They have started to put it in the info page of each applicable restaurant. I assume there is probably a listing here or on the main site that has them all summarized.
We actually ate Thanksgiving dinner at Raglan Road. It sounds weird because it is an Irish restaurant, but I looked over their menu and thought it sounded delicious. We were not disappointed. Stuffing (my favorite part) was especially delicious. Many people say Liberty Tree Tavern, but I have also read reports that their food is just okay, so we decided not to try it. And not having to cook it ourselves and clean up was wonderful.