1. Ask your pediatrician to refer you to a nutritionist who might be able to come up with some ways to supplement or adjust your son's diet to counteract the appetite suppressant effects (for some kids) of the medication.
2. Talk to a pediatric psychopharmacologist (a professional who specializes in these kinds of medications for kids) to find out if there are other choices besides the Adderall that might help in the summer.
3. Sign your son up for a kid's yoga class to teach him better relaxation skills, and consider signing him up for martial arts (as long as it's taught by a peace-loving teacher who focuses on self-control and self-esteem).
4. Intensive exercise that comes from such activities as swimming, tennis, hip-hop dancing (yes!), or running can help produce the brain chemicals that can help your son get more calm and focused.
5. A creative dramatics course or workshop in the summer can also help. Having your son assume the traits of certain characters can help him to learn what self-control ("be absolutely still, like a rabbit that has smelled a fox") really means.
6. Look into natural products that claim to have a positive impact on attention; just make sure you contact a reputable person. You might ask your pediatrician for the name of a holistic practitioner.
7. Consider hypnosis or biofeedback as well. (There isn't much research to confirm the long-term effects of these approaches, but kids seem to love doing them and some find it helpful.
Don't forget to consider a few days off for an "adults only" vacation. You'll need the rest!