My SIL has her parents (my inlaws) look after the kids every holidays. They used to live 4 hours away so they were living with the inlaws for the whole time, and it seems to me that they began to resent the arrangement. I don't think I'd like to do this, mostly because we live too far away. Maybe things will change by the time school comes around.

I have two other friends that use the care provided by the school the kids go to. The kids love it because it's a new activity every day and they see their friends. Because mine are already in daycare 5 days a week anyway, I think we'd probably use this option, it wouldn't be completely foreign to them.