"For Whom the Bell Tolls? Don't you mean, For Who the Bell Tolls?" Okay, Teach, challenge number one: the title of Hemingway's masterpiece utilizes a dying pronoun. 

These days, it seems that whom is neither here nor there, yet the very fact that this word is disappearing from contemporary vocabulary provides you with an excellent opportunity to talk about grammar in context. Why is whom on its way out? Is it because texting and Twitter feeds dominate? Or is it something else entirely? While there may or may not be a "right" answer, the questions surrounding this word have the potential to provoke a rather interesting classroom discussion.