October 12, is more important because it's the day of the Virgen del Pilar, and it's the mayor fiesta of Zaragoza (I recomend them). It's also the fiesta of my neighbourhood (Barrio del Pilar).
I think in Segovia there isn't any special thing and also I think there isn't any celebration about Colon but it is also the day of the hispanidad and there will be some militar marches and things like that...