I don't have children myself so I asked a guitarmaker friend who lives in Granada and this is his reply.http://www.overallcamp.com/
Probably not ideal because it is out of town but great because you could dump english-speaking kids there for two weeks and they would be in a very spanish environment but at the same time communication would not be a problem because they have English teachers there. I used to work there teaching.http://www.memoriadeandalucia.com http://www.parqueciencias.com/
These two places have week-long summer courses for young children (4 to 5 hours per day) which are very good. My nephew went last summer. I can't find any info on the page though, you might have to call.http://www.ciempies.net/escuelasverano.htm
this is where we send Tommy in July and he seems to do fine. Again, very little info on the page.http://sites.google.com/site/caugranada/programacion
These people do stuff for kids, although I don't know about summer.
There are a number of high-priced country clubs in town that bend over backwards for kids (if you are a member). You never know if that would accept temporary members.http://www.rstgranada.com/esp/index.asp?secc=/inicio&popup=1 http://www.clubdecampodegranada.com/ http://www.rstp.es/portal/ http://realsociedadhipicadegranada.com/
Some of the private music schools in Granada might do summer courses.
hope this helps,
John and Monsa
This is the web site of John the guitarmaker.http://www.johnguitar.com/