We recommend going up to San Gimignano, as it is very pretty at night. Our recommendation, the Enoteca di Vinorum, in the Piazza della Cisterna, 30. You can try local wines by the glass and eat the famous bruschettas (similar to Vasque pinchos), affettatti (cold meats) or carpaccios. This will work out around 15-20€ per person. Very nearby in the same square is the Gelateria di Piazza where you can try an endless variety flavours of home-made ice-creams!