That question is difficult to answer when you don't ever really stop.
We have less structure and fewer scheduled outside activities in the summer. Today most of the public schools in our area started. The one that affects us the most starts on Friday. So when do we start our new "school year"? Today? Friday? Next Tuesday when PE starts? The Monday after Labor Day when Scouts starts? Or when I get our supplies, plan, and schedule at home set up?
In the past our marker has been HANCK's Not-Back-To-School party. There isn't one scheduled yet. That is partially due to so many different schedules in the area, partially due to the weather being so hot last week, and partially because no one has said, "It is at (this) park on (this) date."