I agree that it is important, but hard, to take a break during the summer! We started Sunday school in March of this year with a purchased curriculum and two broad age groups (3 year olds - kindergarten and 1st to 5th grade --- we have one fifth grader in the church and there was nothing for her before that, as children's church during worship ends after second grade). Average attendance 3.4 and 3.8 per week, respectively.
The adult Sunday school teacher is disappointed we are taking a break as two sets of parents started attending his class (the other three families represented were attending a group that stopped for the summer or were helping teach kids' Sunday school). So next summer we may want to figure out a way to continue. (Getting the parents to lead means they will still be missing that adult Sunday school class, since we have such a small pool we are working with, but is a great idea for others.)
I hope to use this time off to regroup and evaluate, as the teacher and I aren't pleased with the curriculum we were using for the older group. I am hoping to find a way to make rotation work for us with our small space and small group, but need to bring some more people on board. And that will take energy that I don't want to spend preparing weekly Sunday school lessons for preschoolers all summer.
Love all the encouraging ideas here about ways to have summer programming without the VBS production!