In my opine, parody is a vastly underrated form of expressing ideas that may have been missed in the original work, or that might be expounded upon under the guise of comedy.
It was good enough for T S Eliot, James Joyce, Miguel de Cervantes Saavedra, Samuel Becket, Lewis Carroll and even Shakespeare.
More modern examples might be Weird Al, the producers of films such as Hotshots, Airplane and the Scary Movie series, Mad Magazine, The Onion, certain Bugs Bunny cartoons, and shows such as The Colbert Report and The Daily Show wouldn't exist without it, or would certainly lack in their appeal.
As a derivative art form, I can see some objecting to the lack of originality of works such as these, but is there any truer homage that can be paid to the original work than imitation...albeit with tongue firmly in cheek?
Discuss, and feel free to post your favorite examples of parody. One of my personal faves is Rosencrantz and Guildenstern Are Dead.