If you have ever watched The Family Guy, then you know that it is one parody bit after another. No part of pop culture is left untouched.
So the show incorporates a few seconds of Carol Burnett's cleaning lady character (people actually remember that?) so she decides to sue. Sue? Did that darn Patriot Act repeal the First Amendment, too?
Not only does Ms. Burnett not have a sense of humor, her lawyer's don't understand copyright law.
Edit: Didn't she do a parody of Gone With The Wind?
Edit: The clip and the lawsuit can be seen here on The Smoking Gun.