In keeping with this, be sure to check out the midterm postmortem in the Boston Review by Brendan Nyhan, John Sides, and Eric McGhee. No doubt political scientists will be learning more about the 2010 election cycle with time, but this is a pretty impressive compendium of all that we know so far about things like the power of the Tea Party, the impact of campaign spending, and the effects of roll call votes cast by incumbents over the past two years.
Also, if you're teaching about any of the 2010 races in the spring, be sure to pre-order your copy of Pendulum Swing, edited by Larry Sabato. It will be available for spring classes. I mention this because it's affordable and because I have a chapter in there about the Colorado senatorial and gubernatorial races.