In the north of Madrid is a big lake where nature and men join. Where youcan spend the day in themost relaxed enviroment with your family or your friends andenjoy the cold water or the short grass while you lie and sleep in the shadow. Where you can play football, cards or dive in the water. ADD is a palcewith some rocks where you can jump fromto the water and is always plenty of children jumping and laughing.
People use to bring their own food and drinks, but any way you have a restaurant and a bar there so if you don´t want to bring it you can eat there.
Finally, if you like animals, farms and this kind of life, you can enjoy walking around and see horses, cows, sheep...
Anyway, you can visit this websites and obtain more information about howw to arrive and any other question that you could have. http://www.rascafriaturismo.org/
Don´t doubt about it, a perfect and cheap day is waiting you,