Festivities of Castejón de Sos Activity · Castejón de Sos, La Ribagorza, Huesca Image of Castejón de Sos, not of the place itself. The patronal festivities of Castejón de Sos, a municipality of Huesca province in the comarca of the Ribagorza, are held twice a year: on 20 January, in honour of San Sebastián, and on 12 October, dedicated to the Virgen del Pilar. These two dates make up the municipality's main festive calendar. Photo: Wikipedia / Wikimedia Commons (CC BY-SA) What to see and do in Castejón de Sos