Over our years of going to Disney, we've come up with all kinds of things to do in line. One year, when we went to Disneyworld over Christmas, I took the trivia cards out of our Disney Scene it game, and we divided into teams and played trivia while we waited. It was so fun and many times, people waiting around us joined in as well. We also play guess the character, where you get ten questions to guess the character. We always play I-Spy. I carry a 4x6 card with Hidden Mickey clues on it and we search everywhere for those. Now that my kids are mostly teenagers, they spend the time in line taking crazy pictures of each other.
Like others have said, getting to know people around you in line and talking to cast members also helps pass the time as well. We are seldomly bored in line when we are at Disney. Maybe some of that is because we've gone so many times, my kids know what to expect. Even when they were young, they would hardly complain. I like to think it's because I had a good line waiting plan...that may or may not have been totally true though.