When hang means, as it generally does, "to suspend," then hung is the correct past-tense and past participial form of the verb: "Yesterday, I hung a picture on the wall"; "I have hung many pictures on many walls." When hang means "to put to death by hanging," however, hanged is the correct past-tense and past participial form: "We hanged the horse-thieving varmint yesterday"; "We've hanged nigh unto forty horse thieves this year." Given that hanging has become a fairly infrequent means to a fairly infrequent end, you might think that this is an unimportant distinction. But, because of a colloquial...