Easy controversy

I have been pondering how to improve the educational experiences of my students. Inevitably, I revert to planning a class that has more discussion and less lecture. I could start each class with a controversial topic from the readings and then guide discussion. The problems is how you evaluate such a class. Essay exams and writing assignments are a time consumptive proposition for me, and it would be difficult to write exams for general consumption. To exacerbate the problem, students don't even have to think critically and independently with all of the available information on the internet. Take for example ProCon.org which is a clearing house for quotes and information on controversial issues. Now even contentious issues have a Cliffs Notes online edition.