The first one I can think of just now, is Kipling's The Jungle Book, when I was was in the 6th grade. It was strongly suggested that we read it over some school holiday. As I recall, I was the only one who actually did, and I won a copy of the book.
That really bugged one of my classmates, me being the "new kid", and all. We became best friends, not long after that. :)