External Material
This is a good way to start a session if no one suggests a topic they would like to cover. Bring in copies of an article or similar document relevant to your subject area, have the students read the article and then highlight any points the found of interest or that they didn’t understand/follow/agree with and then discuss the points raised.
There are also some great clips on YouTube and TED.com, which can provide a great opening to a session that encourages your group to see beyond just the material presented in class.