I decided this year I would be less strict during summer for school work. Last year I let the boy have a week off and then it was business as usual. We both got burned out and I think it contributed to a harder school year last year. So this year I'm only requiring math and reading/writing.
Here's my summer plan:
Math: Singapore Math 4A-B was our curriculum this last year and I thought after April we'd just move right in to 5A. But 4 went way too fast and I don't think most things were learned concretely. Maybe I can't completely blame Singapore's curriculum. I have talked with A LOT of parents and students (some profoundly gifted) who seemed to struggle with the transition into fractions/decimals. All of them recommended we go back to first grade and just review everything learned up to that point and that things would start to click after that. So we're in the midst of that. We're using Khan academy, Life of Fred Fractions, and a Singapore Math review book. I'm already seeing improvement and think this might be a good idea every summer....
Reading/Writing: I have a summer book list for both my reading kids. We are making our way through that list and when they finish, they get a prize (swimming pool trip). Jack has the additional incentive of writing a book report for each book he reads to earn computer time during the week. I went through lists from Hillsdale Academy, Spalding International, and the Well Trained Mind and then created my own reading lists.
Everything Else: This is when I get to unschool. We drive in the mountains and talk about different biomes. We talk about why the sky is blue. We talk about the yeast start being a living organism. We also own the complete series of Magic School Bus and Liberty's Kids and because my kids have learned so much from them, I have no issues with using them. Jack has become very interested in politics lately and likes to talk about current events. We'll worry about world history, famous artists, and formal science lessons when we start up again in September. But for now, I'm enjoying a more relaxed atmosphere.