Aha, so that Columbus day you have, is what we would call a Bank Holiday here.
Yr week the kids have off school that you call fall week, we call it half-term week (end of October and then one half-term week in February) and the week they have end of May, beginning of June is called Whitsun week.
Yr inservice day, we call it inset day (the school has a few of those per school year).
Some schools in our area alternate with Martin Luther King, Jr's birthday. One year kids will have off Columbus Day; the next year they'll have off MLK, Jr's birthday. Some schools have just completely gotten rid of a day off for Columbus.
I always wondered about the way historians use the word "discover." How can you discover something that's already there and has been for 100s/1000s of years?! :confused