I really don't like the typical school year schedule. The scool year is toooo long, kids get sick of it, then summer is tooo long, and they get sick of that too. I would much rather have year around school with more frequent, shorter breaks.
Anyway, that's not an option here so we try and keep busy with:
Band classes for a few weeks
Basketball camp for a week
swim lessons for a two weeks
scout camp
bible camp
a few trips to brother in law's lake cabin
other things I can't think of right now.
And last year I started with one science lesson/experiment a week. That was great bucause the kids got to have a friend over and we all do the experiment together. I love Bill Nye the science guy and get ideas on the website and from his books.
This year I'm adding one art lesson a week. We just did this lesson last weekend when it was snowing (!) and we all had a good time with it:
http://www.homeschoolarts.com/cp-2-1.htm
Then if they start getting too board and playing too many video games I get out the books and we have read or problem solving hour.