You can buy a cumulative ticket that covers the Torre Grossa and its Museo Civico; the little Pinacoteca painting gallery in the Palazzo Pubblico; the tiny Museo Archeologico detailing the region's Etruscan era and the adjacent Spezeria Santa Fina (a preserved Renaissance pharmacy); the new Galleria d'Arte Moderna modern art gallery; and the weird little Museo Ornithologico, a couple of glass cases containing stuffed birds in the dimly lit confines of a tiny, deconsecrated church -- basically all the museums in town except the Collegiata, the Museo d'Ate Sacra, and the privately run Torture Museum. The cumulative ticket costs 7.50€ ($9.75) adults and 5.50€ ($7.15) ages 6 to 18 and over 65. Prices listed below are for individual entries to each.
Take a Hike -- The tourist office sponsors guided walks through the countryside April through October, 2 to 3 days a week (usually weekends), costing 10€ to 15€ ($13-$20) per person. Because the country edges right up to San Gimignano's walls, you could also easily set out on your own to wander with a good map -- the tourist office also sells a map and catalog marked with suggested hikes and walks, or you can pick up a regional map from any of the local souvenir stands.
A Great Point of View -- Behind the Collegiata, the remains of the city's 14th-century fortress, the Rocca, are now a public park. Climb atop the crumbling ramparts for a view of the surrounding farmland and the best panorama of San Gimignano's towers.