I'm a homeschooler, and I use some curriculum now. With the exception of math, the curriculum I do use is more for me to determine what we do next. Unless something better comes up, of course! We tend to go deeper than our curriculum in most cases.
I was going to try something different this summer. Our standard mode of operation is not going to work this summer when school kids are pounding on our door all day!
Anyway, I'm going to write up a checklist at the beginning of every week and say what I'd like done that week. Something like 2 directed journal entries, 1 blog entry, 3 math exercises, 1 science experiment, piano practice (the one thing we are religious about). I'll be more specific week by week. I am going to use more math problem solving at our current level, I got the book Irresponsible Science (I think I got that recommendation here!?) which is perfect for hands on summer science fun with the neighbor kids.
My 8 year old regularly reads for an hour a day and he usually reads "good" books. I think I'll encourage him to read a non-fiction book once a week this summer too. We'll continue going to the library and following his lead. Right now he's interested in programming with Alice and Lego Mindstorms. And still honing math speed with games. We may get some sort of typing tutor program this summer too. Part of my thinking here is to get him thinking about time management skills (which has actually improved lately - he's jumping into his work in the morning to get his less favorite parts done). And I really am only going to probably write up enough that could be finished in 2-3 hours time. If we have down time, I'll throw some more at him or we'll pursue a bigger history or science project.
Anyway, summer is a great time to dig into whatever your kids are interested in and use those libraries to their fullest! It's nice to have some appropriate math work books, but you don't need much more than that! Outdoor, messy projects are great too. Good luck!