Festival of San Giuseppe
On March 19th, there is the Festival of San Giuseppe, starting at 8 a.m. at Via Duprè here in Siena, in the Contrada of Onda. There will be ceramics and Sienese pottery, and stands selling toys and sweets.
The museum of the Contrada will be free and open to admission.
For more information, check out Siena's official tourism site.