We are travelling with a large family group during Christmas week and I am looking especially for activities that will engage my 16 year old daughter. Dinners we are totally covered so what I really need are daytime activities that will be open during Christmas week. We are staying near La Foce. Thank you so much.
There are some events taking place in Siena at Christmas.
https://www.comune.siena.it/node/3555
If you like the thermal spas there are numerous natural spas or also resort spas in the area, at Bagno Vignoni, Chianciano Terme, Terme di San Filippo, just to name few.
Wandering the streets of Montepulciano or Pienza could be fun. 16 year olds are hard sometimes to entertain and you are in the middle of rural Tuscany. Not a lot of glamor there. You would be better off in Rome, Florence, or Milan. Lots of stuff there to entertain a 16 year old at Christmas time. Good luck..
Maybe she would like staying in an Agriturismo?