I absolute love the Orson Scott Card novels Ender's Game and Ender's Shadow. I did not really get into these books, but my students loved the Maximum Overdrive books by James Patterson. They also love Madeline L'Engle books as well.
You may want to also read some of O. Henry's short stories which are delightful.
Don't know what interests you, or what your reading level is, so I'll just give you a variety to choose from.
The Robert B. Parker series of westerns: Appaloosa, Redemption and Blue Eyed Devil are all fun, quick reads.
Lastly, the novella Of Mice and Men.
If you're looking for young adult fiction, try Sharon Draper. If you are interested in historical fiction, you might like The Book Thief by Markus Zusak. It tells the tale of a girl who finds a gravedigger's manual in Nazi Germany and sets out a path to save books from Hitler's book burnings. It's an excellent read!
It's impossible to tell two important things from your request--what kinds of things you've already read, and what kinds of things you might be looking for. I'll list a few which you may or may not have read, may or may not like:
The Lord of the Rings Trilogy, Harry Potter series - fantasy
Anything modern in whatever genre you prefer (science fiction, action, mystery) would be great fun as a break from your school-related reading.
I apreciate that you want to read during the summer. It's a great way to keep your mind working and improve your vocabulary at the same time. Enjoy!
If you are looking for recommendations, I have a few:
Tom Clancy - Pretty famous at this point, several of his books were made into pretty good movies, but the books are still far better. If you like action-thriller novels, sometimes with more spy intrigue, sometimes with more action, he is difficult to top.
If you like historical novels, the Hornblower series is pretty good, based loosely on events that took place during the British war with Napoleon in various parts of the world on the high seas, they are fantastic.
I am also a big Faulkner fan, but not everyone likes his style.
If you are going into tenth grade several good novels I have had my students read over the years include:
A Separate Peace by John Knowles - great story about best friends in a boarding school at the onset of World War II.
The Things they Carried by Tim O'Brien -- this novel has elements of fiction with a fact based narrative referencing the experiences O'Brien lived through while growing up in Minnesota and while in country during the Vietnam Conflict.