If you have not planned to go to Toledo, you should take one day to go there. And there are day trips to places like El Escorial and Segovia which are also possible, but if you were going to do one day trip, I'd recommend Toledo.
There are the Teleferico cable cars or you could take a guided tour of the Real Madrid stadium
You might plan to have lunch at the Parque del Retiro which has a boating lake and fountains. On Sunday?s you?ll also see Punch and Judy shows, tarot card readers and stalls selling candy floss.
If you are there on Sunday you must also go to El Rastro, the outdoor market.Even if you don't care for art museums, you really have to look at the Prado. I particularly like looking at the Spanish artists, or the ones that painted in Spain (like El Greco). Goya has some very Goth stuff there. I also like looking at the Bruegel's even though he's not Spanish in the least. I think if you limit your time there and pick one area to go look at, a museum visit won't be too bad
I've always been sorry that I did not get to the Reina Sofia Museum where Picasso's Guernica is exhibited.

