Paper chain letters: I drop them off at the post office if I have to go there in the next few days, or I toss them in the trash.
Email forwards: if they’re the “OMG OMG <insert urban legend here> OMG!” type, I debunk the legend, ask the person to do some research before sending another panicked email, and cc it to the entire list of people they sent it to. This usually gets me taken off of distribution lists for email garbage.