there are certain things they are supposed to do over the summer (granted, many don't. gets back to that accountability issue), and there's the chore of closing down a classroom, preparing it for classes again and, really teachers should use the summer as a open time to improve their lesson plans, etc...etc... Of course, the fact that none of that really is on the clock means it does't always happen. Broken record, accountability issues.

Of course, if we move to a more year-round schedule like a lot of the rest of the world, they'll be working on the clock more anyways. Personally, I support moving a year-round schedule. We don't really need summer vacation.