depending on what grade levels you teach,You could try to get a job at a Day-care center. I think that would be very helpful. You could test out new classroom management techniques there or just keep yourself around lots of kids so you're more prepared for the school year. You could also try employment for summer school, obviously this would keep you in the classroom and keep you sharp. Additionally, I'm sure there are several summer workshops you could attend to get new ideas and techniques.
This summer I intend on applying for different summer camps. It is a great way to interact with children outside of the classroom and learn knew and exciting activities that may come in handy in the classroom. I will be graduating in the fall with a special education degree and I know there are a ton of summer camps offered for children with special needs. It is an option for any kind of teacher and great experience.