Study after study shows that kids lose a huge chunk of the previous year's learning during the summer if they just play and don't do any reading or studying. But summer is for giving kids a brain break, right?
Not really. Summer vacation was originally instituted so kids could help parents with planting and harvesting. In today's society, not many of our kids are doing that so it's really just a tradition that few schools have gotten away from (except year round schools). It wasn't created so kids could stop thinking for 3 months.
I've found that kids left to their own devices all summer long often get bored or in trouble. So our summer traditions include these brain activities.