This is one of my favorite lessons. It's always interesting how much the discussions stay the same, and how much they change - both throughout the day, and from year to year. I taught this almost exactly the same way I taught it last year - because I liked it so much.
As such, I'm linking to last years post. We didn't finish it off - getting to the point of Samsara and Moksha, but we will tomorrow. I guess, if you read the blog, you'll be ahead of everybody else.
Read THIS POST and do what it says in order to earn the extra credit.