It's a time of evaluation of the past year, and of looking ahead and setting new goals for the coming year. What I try to do is focus on the things we have accomplished instead of dwelling on the things that went undone this past year. Even classroom teachers have the same feelings. Only it's worse for them in some ways because this year is the last chance they will have with their children in the classroom, someone else will have them the following year. We continue our weekly trips to the library as well.
Summer is also a great time to do some at home science experiments or take field trips.
I also like to review the goals I set for each child the previous year, and see how far we've come and what other goals should be set. If you haven't done this formally, it's no problem. You're around your children enough to know their strengths and weaknesses. We have 17 years to work with our children and help teach and train them to have the necessary tools and skills to be successful in life. Also don't compare yourself with the other families you may read about on here or in homeschooling magazines or books.