Most of these characters never said these lines, but they could have (all based on the general plot description of their film or TV show) - if they didn't actually do their homework in addition to their unique extracurricular activities!
Discuss here: http://www.imdb.com/board/bd0000088/thread/223021010
Results of 7,307 votes:
1.Michael J. Fox, Back to the Future My friend, a mad scientist, accidentally sent me back in time when he built a time machine!
2.Jake Gyllenhaal, Donnie Darko A large bunny rabbit is haunting me and manipulating me into committing crimes!
3.Leonardo DiCaprio, Catch Me If You Can Homework? You must be mistaken, I'm the substitute teacher! - credit to Rafael_M