I’m traveling next month and I have a long overnight layover in Madrid. Since sitting around the airport for 19 hours sounds miserable I plan to get a hotel room and take myself out for a nice dinner. I’m looking for advice from those who know Madrid. What should I see with such a limited time available that will be open in the late afternoon to evening hours?
I really enjoyed the Market of San Miguel. It’s a conveniently located, beautiful old cast iron conservatory type building. It has a couple dozen stalls, with each vendor selling a particular type of specialty food or drink so you just graze your way through the afternoon/evening looking at all the amazing food even if you can’t possibly eat it all.
makes a note for next time she’s in Madrid
In general, the area around Plaza del Sol (San Miguel is about 200m away) is going to be busy and have a lot of stuff going in the afternoon / evening. There’s bound to be shows going in any of the theaters nearby; my favorite theater in Madrid (Circo Price, which yes, used to be a circus) is a bit further but its shows tend to be heavily in favor of body-language and music, they’re more likely to have an acrobatic show than something from the 16th century.
One advantage of eating tapas-style is that you’re not bound by cook’s hours. Spanish hours tend to involve doing anything two hours later than other people, something which has been known to produce frustrated foreigners before the stores open and fainting ones before the restaurants do.
If you’re feeling whimsical, one of the things which is right there (afternoon hours, 17:00 to 20:00) is the Casita-Museo del Ratón Pérez. El Ratón Pérez (The Mouse called Pérez) is Spain’s version of the Tooth Fairy.
Don’t trip over any of the people selling fans on the sidewalk, like I did.
And watch your wallet in the airport… like I didn’t. 
I have a similar layover coming up in October. Let us know what you decided and how it went.
I heeded warnings about European cities and wallets so I had my wallet on the inside pocket of my zipped lightweight raincoat most of the time (the rest of the time it was on the inside pocket of my unzipped raincoat due to the heat, and I didn’t care that I looked goofy since I wasn’t venturing outside of touristy areas.)
I have a 1 hour layover there 5.am-6.am in July. Am eagerly awaiting any suggestions for things to see inside the terminal 
Given that generous timeline, may I suggest a visit to the restroom of your choice followed by queueing for your next flight?
I had my wallet in a zipped front pants pocket. They got it from there.
I’d like to suggest verifying which terminals are involved according to your tickets, then mentioning to the stewards that you’ve got a connection and can they verify it for you once you’re on approach? It may also, if one is a practitioner of any religions, be appropriate to invoke your deity/ies and ask them to pretty please ensure that the second flight doesn’t depart from Torrejón (the AF base isn’t an official terminal but I’ve had flights leave from there; twice).
Having to run from the fucking end of T4 to the blasted other end of T1 and who the shit thought this was a good idea was not fun. Cabin personnel can contact land personnel and get you on a golf cart or a bus if needed, and if your golf cart driver is like the one I had last week in Barcelona he’ll love having an excuse to go as fast as the little cart and the amount of people (quite a surprising amount even at such an early time) will allow.
“19 Hours in Madrid” sounds like the title to a drama that I’ve never heard of, yet somehow gets 8 Academy Award nominations and is a frontrunner for Best Picture.