12 de Octubre means "bank holiday" and therefore there are a lot of plans you could do on this day, enjoying the day 100 %.
At 10:30 from Cuzco to Nuevos Ministerios you can attend to "Parade 12 de Octubre". with the military forces, the royal family, president etc.
If you like Art and Design you could go for free to several museums on this special day, for example Museo Reina Sofia and Museo Thyssen-Bornemisza.
Wants adventure? Parque de Atracciones de Madrid and Warner Bros Park is open tomorrow for the special occasion.
Theater maybe? La Duarte - Eva Peróns life at Teatro Canal, Cea Bermudez 9. If you can't go tomorrow you have til the 16th of October.
Or a muscial? Hair at Arteria Coliseum, Gran Via 78, Shrek The Musical at Teatro Nuevo Apolo, Plaza Tirso de Molina 7 or Mas de 100 Mentiras - Sabina at Teatro Rialto, Gran Via 54.
And if you like Opera tomorrow you have Elektra at Teatro Real.
Keen on sports? Maybe the Supercopa in Rugby is something for you. 12:30 at Complejo Deportivo de la Universidad Complutense.