Oh, here we have 'Summer schools' (Escuelas de Verano), but they are something completely different.
Here they are basically special activities mainly aimed at kids and teens so they have something to do over the holidays (some parents may work over Summer and can't look after their children in the morning so they send them to a Summer School.
There are different types too. I have been to a few:
The 'normal' type ones are basically a group of activities like playing games, visiting places etcetera.
Language Schools are also quite popular. A lot of people sign up to English or German language schools here (and to be honest, I'm drooling over this Intensive japanese Course @.@)
Sports are also popular too. Last year I went to one - we didn't do that much sport, but it was OK. I tried signing up again this year, but all the places were taken up.