San Gimignano is a small medieval hill town in the province of Siena and also a UNESCO world heritage site. It is famous for its towers of varying height which were constructed in the 12th century by rivalry families who wanted to demonstrate their power by the height of their tower. To date 14 of them are still preserved which form a pretty skyline and make the town recognisable from afar.
The medieval town Volterra is tucked away in the scenic hills right in the center of Tuscany, only about one hour drive from Pisa. It's a great place to escape from busy city life and wander through the small streets with a gelato while admiring the alabaster workshops. For food I would recommend restaurant Don Beta (http://www.donbeta.it/il_locale.html) and you can't leave without trying their 'tartufo' (truffle) or fresh pasta with wild boar sauce. In the summer months book a table to avoid disappointment!