Please forgive the shameless plug, but if you're teaching about the 2010 elections this spring, or if you'd just like to know more about them, please consider Pendulum Swing, edited by Larry Sabato. It contains fascinating studies about many key races by leading academics, analysts, and journalists. There's also a chapter by me. I wrote about Colorado's gubernatorial and senatorial contests. You can see cool polling graphs, like the one at left!