This is a very popular activity with students of all levels.
Students must argue their choice for who is MOST responsible for the baroness' death: Baron, mad man, friend, boat man, baroness.
I often will have the groups work towards a concensus then take a vote for most responsible. I like to walk the students through each character and act as devil's advocate to get them thinking about all angles. Students have the opportunity to get in their thoughts as well. At the end I take another vote to see if we have changed anyone's mind.
This is a good lead-in to persuasive techniques and opinion writing. I often use Monty Python's Arguement Clinic along with this activity (available on youtube, printed script can be found on many websites)