Last time I was in Madrid was in 2003, working on server migration for the worlds largest container freight company (and later same year I attended TechEd EU in Barcelona).

In spare time I got the chance to see some really cool things, some you might also find interesting:

- The Royal Palace, "Palacio Real", one of the largest in Europe, have 2000 rooms.
- The New Cathedral, "Catedral de la Almudena", it took 110 years to build it.
- "Plaza Mayor", an old Square that earlier have been used for bullfighting.
- You can take "Teleférico" (Cable Car) to "Casa de Campo" (a large public park), where you will find Madrid Zoo Aquarium, "Parque de Attracciones" (Madrid Amusement Park), and if you fancy also the Bullfighter School, "Venta del Batan".

Interested in Football (Soccer) - go visit "Estadio Santiago Bernabeu", home of Real Madrid or go to "Vicente Calderón Stadium" where Atlético Madrid resides. 

Spain is known for good wine and dine.
And Bullfighting (but it is now banned in some areas of Spain).
If you are curious and want to see it yourself, go to The "Plaza de Toros de Las Ventas" in Madrid, it will be an experience you never forget.