I live in Colorado and the local school district starts the week before Labor Day and kids get a weeklong break about every 6 weeks. They get a fall break (around 1st/2nd week of Oct), Thanksgiving break, Christmas break (~2 weeks), late Feb break, spring break in mid-April. Graduation is on Memorial Day weekend and the rest of the school lets out about the same time. Of course, there is rarely ever a snow day to extend the year. It's a ski town so a lot of parents have to be around for the March spring break and very few leave over the Christmas break.
They've been doing it this way for 2 or 3 years now, and have seen positive results. Kids take their week breaks and come back refreshed and ready to learn again. Of course, parents also have the ski resort/ski school as their "baby sitter" for those weeklong breaks.
