Looking for a movie title. It's about a young boy, and this magical box(or something) enters his apartment. He somehow goes through this box, and he becomes cartoon. He then goes on an adventure. At the end of his adventure, he returns to his apartment(non cartoon) and he is on the phone with a friend, and learns that the box has now visited his friend.

The Phantom Tollbooth (http://www.imdb.com/title/tt0064806/)