Any suggestions for a Tuscan vacation?

We are going to spend a week at a villa in the Tuscan countryside near the following towns/cities - Chiusi, Sarteano, Spineta, Fonte Vetriana, Cetona, Malapesa, Colle Sant'Alberto, San Francesco, Santo Stefano, Montepulciano, Italy in late June. Does anyone have any suggestions for day trips near these towns or other towns? We like things cultural, historical and artistic.