Just search the fora my Hockey Night in Canada-watching friend to the north
...you'll find a variety of things to go and see/do.
If you're looking for free things like hiking, etc., I suggest you do that in Asturias. As far as sights and sounds, there are still a lot historically significant sites that you can explore at little or no cost. Even the Prado is free on Saturday afternoon!
Check around and I'm sure you'll have enough to say "maybe I should add a week to my vacation...or a month!"
Welcome to the board and I hope you find the useful info you need!