My 6 year old twin boys have always loved story time. They are now reading short stories and easy readers on their own. But I am looking for books to read to them. They read a short book to me, and then I will read a chapter of a more advanced book to them. We have already read and loved the Captain Underpants books, and started on the Diary of a Wimpy Kid series. I am looking for more suggestions. Something that will hold there interest, but still a bit advanced for them to read on there own.