A lot of teachers look for part time jobs during the summer. Tutoring or teaching summer school may be tempting. Not a good idea.
I understand that the money may be good for these kinds of jobs. Unless you are really hurting for money in a major way, though, I wouldn't recommend doing them.
Teachers who want to stay in the profession for a long period of time should do whatever they can to stay fresh. This includes taking breaks from teaching related activities whenever you get the chance.
Work intensely during the school year to make sure that you are doing the best job you can. When it comes to breaks, though (including the weekend), think big picture and do what you can to avoid getting burned out.