The famous allegory of the cave is hardly the highlight of Plato's great Republic, though commentators sometimes treat the extended metaphor -- a person in a cave is temporarily blinded when he sees sunlight for the first time, and is then ridiculed when he returns to the cave and can no longer distinguish the shadows on the walls -- as if it were a capsule summary of Plato's entire philosophy. Perhaps the brilliance of the philosopher's writing has itself blinded these commentators, because the allegory of the cave is mainly an illustration of the difficulty of understanding a provocative philosophy, and hardly represents the essence of Plato's philosophy itself.
If I had to name one single idea as the core idea of The Republic, I'd name the notion that the human soul is like a government, and that different types of dysfunctional souls can be compared to different kinds of dysfunctional governments (I've written about this message here before). The "Republic" of the work's title is, in fact, meant to designate the republic of conflicting voices and urges found inside each individual person's mind, and the text was actually written as a work of psychology, not (as is commonly thought) a work of political theory.
With that said, I stumbled across a pleasant cartoon of the cave allegory this week, and thought it would make a fine entry in the Philosophy Weekend series. This 8-minute cartoon was made in 1973, and features the voice of the esteemed actor and director Orson Welles and animation by Dick Oden, who spent much of his career drawing fanciful classical record album covers. Enjoy it, if you've got eight minutes to spare, and I hope you won't be blinded by the light.