San Sebastián is not a town of theme parks and sandy beaches, but just exploring the relaxed and colourful streets is stimulating enough for most folk over the age of 10. For a panoramic orientation of the town, head up the road to the Parador Nacional Conde de la Gomera hotel, where the Mirador de la Hila showcases the coast, the town and the craggy green mountains beyond.
In the town centre, most of the interesting sites are somehow related to Columbus (in either real or contrived ways), and they form a route you can follow around town. Begin at Plaza Américas, where you can get a juice in one of the terrace bars, and across through Plaza Constitución, shaded by enormous Indian laurel trees. There's an arts and crafts market held here on Saturday and Wednesday mornings.
The tourist office runs free tours of the old quarter on Wednesday and Friday at 11am.