Here is Lawrence Lessig speaking at Google. The title of his talk is "Republic, Lost: How Money Corrupts Congress—and a Plan to Stop It," but to me, that doesn't begin to encompass everything he talked about.
Somehow, though, the talk is only 45 minutes long. There's also a 15 minute Q&A at the end. Highly recommended, no matter your political leaning, even if that leaning is fully toward apathy.