Does anybody know the name of the bar that is sort of near Plaza Mayor, I believe the name is a number, like 13, or 21. It is a very narrow bar, and the bathroom is a closet that has white tiles and a drain in the floor?

You're having fond memories of "El 21", located on Calle Toledo, 21, just off Plaza Mayor. Sadly, I beleieve it closed down. It was run by a jolly old couple who served up little shots of drink, some of them burning, with names like Volcan, Diablo, and, with a raucous cackle as the señora plopped it in front of you, el Erotico. Too bad but that's progess.
Maybe someone in Madrid now can go by and check if it's still there and let us know.

Thanks, my friends are going over next week, I will get them to saunter by and I will report what I hear. That was definately the place. Thanks very much!