This assignment puts students together in pairs to develop presentations in which they debate each other on a topic they select together. It teaches polemical and research skills as well as public speaking and PowerPoint. I have been using this assignment for years and have refined it carefully to make it profitable and fun for the students, as well as interesting for the instructor to teach, view and evaluate.
The 4-page document includes detailed instructions that I've found successful in preventing common errors and in heightening the quality of the presentations. Also included is a peer review form for the debate. When students put sufficient effort into this project they end up impressing themselves and learning a great deal. They love watching each other's debates, too.
As a teacher I love this assignment for many of the reasons mentioned above and also because I can get most of the grading done in class -- this is much better than taking home a stack of papers.