The tico times put out an article on where to find thanksgiving dinner on Thursday. So if anyone is in town here are a couple I remember and you might be able to find the complete list on the tico times website
http://www.ticotimes.net/ .
In the gulch
SL will have I believe all you can eat for about $22 dollars drink included.
Chubbs by the del rey will have compleate meal and drink I think 10000 colones. Turkey's are from Don Fernandos a great place for meats.
Some of the nicer hotels around town were mentioned but none that we frequent. And the white house very fancy in the hills I think was $25.00 complete without drink.
Have a happy Thanksgiving.
AZcentral