Below are some helpful videos and links to help you keep your skills over the summer! Even for those of you that don't have an instrument for the summer, there are several resources that you can use without an instrument.
Noteorious: Note reading game and has options for all clefs.
Music Theory Review: There quite a lot on this website, some may be beyond what you have done so far.
MusicTheory.net : If you explore the three pages listed along the top on the left side for “Lessons, Exercises, and Tools” there are many things to explore on this website for free.
8notes.com:This website has a lot of free music for you to explore. Can be good for sight reading!
The Music Interactive This site has several good (and free!) apps to download to PC/iOS (Staff Wars). Look through the "Classroom Apps" and "Performance Apps" and see what might be of interest to you! (This has STAFF WARS!)
Cello Bello Cello geared, but very good information about technique, musicianship, artistry, etc!
String Skills Lots of wonderful information about all the string instruments, sightreading, shifting, technique, you name it... it's probably here..