Ah, summer! I don't know about y'all, but I absolutely cannot wait! I know that my kids can't wait, either.
However, if your child is already in a music program, it's a good idea to try to keep that momentum throughout the summer. The reason why is simple: Music and math are not like riding a bicycle. If it's not continuously applied, students tend to forget even some of the most basic skills that they've learned throughout the school year.
I can tell you about this, first hand. I remember that I sliced all the way through my hand back in 2001. I had to have a fun little procedure called tendon repair surgery. It was the pits. Anyhow, I was not able to practice for the better part of six months (no, it SHOULDN'T take that long to heal, but I disobeyed the doctor's orders, tore the stitches, and they had to do it again. TOTALLY my fault). As a result, not only was I rusty as far as coordination goes, but I was rusty as far as sight reading went, also. Music has always been my passion, and I found that time period to be very upsetting.
Kids see the summer as unlimited video games, TV, and time to spend with friends... But, now that I have my own kids, I see the summers as an opportunity for continued education, in addition to the fun.