I teach in a lecture hall with 200+ students and am looking for more ways to engage my students. I ask questions for verbal answers in class and we use CRS (i.e. clickers) but I'm always looking for new ideas, particularly for my 8 am lectures.
One technique I've used that works very well to stimulate participation (although not in a class this large) is to pit one side of the class against the other side in a competition in answering questions. It always surprises me how humorously competitive they do become and how quickly they bond as teams. They always look forward to the competitions. It might be difficult to do this in a large class, though, although perhaps the clicker technology would allow this.
In a large group you have few outward options, but I do think that you have to look at yourself and make sure that you are being as interesting, clear, relevant, practical, (and perhaps funny) as possible. Review the material you need to cover. Ask yourself where you can tell an interesting anecdote. Ask yourself where a demonstration might be helpful. Ask yourself if there is a movie clip or PowerPoint slide(s) that could help make your point. As you already know, being engaging is really a process of reflection on your part.
Clickers, circulating around the room during lectures and soliciting responses, even cold-calling on students every now and again work fairly well. These days, most lecture halls are equipped with theater quality A/V equipment, so incorporating films if appropriate are always appreciated by students. Ultimately, I think to be an effective lecturer, you cannot allow students to hide, or at least make them think they can't hide. I have also seen lecturers who have students get into breakout groups to discuss documents, parts of the lecture, exchange notes, etc. Sometimes it worked, other times not so much.
I agree with most of what has been said. There is little you can do apart from lecturing. However, this point should not be undermined. A good lecturer who is lecturing on an interesting topic can captivate an audience for 90 minutes or so. Also I would try to use the Socratic method by asking question and randomly selecting students. It is not bad to put people on the stop. The right amount of tension is great for learning.
I've never taught anything nearly that large, but I've been one of the students in such classes! Particularly at 8AM, you may need to just resign yourself to the idea that you're not going to reach high levels of involvement! That's what labs and smaller discussion groups are for.
Clickers and texting are good possibilities and previous posters have mentioned group activities that might lend themselves to use, depending on your subject and the requirements of your curriculum. If your large class is intended to be a lecture class, it's meant to impart large amounts of knowledge from the "sage on the stage" (you) to the students - active engagement at the time not expected!
Having taught this sort of class when I was in graduate school, I would tend to agree that there's no real sense in trying to do anything past the use of clickers. I think that students get a bit annoyed when you try to do something other than lecture in a lecture-sized class. Clickers are great in that you can get input from the students without having to really put them on the spot in front of a huge class. But other than that, I think that you have to stick with the sorts of things that people have always done to liven up lectures -- things like having brief film clips or graphics or simply just changing pace here and there (clickers are great for that).
When I read the title of your post, I was ready with a one-word answer, "Clickers." You're already using them, so I'll have to think of something else.
I remember being one of those bodies in large lecture halls for first-year chemistry and physics courses. I was a serious student, always attending the lectures and trying hard to keep focused on the material. The most engaging moments for me seem to be characterized by one or two things:
1. Demonstrations: I always enjoyed seeing demonstrations that worked seamlessly with the material, especially is something popped, smoked, or changed color. These were the days before document cameras and video projectors, but the lecturers sometimes made very good use of what they had, such as using an overhead project to allow everyone to see how a particular chemical reaction lead to a dramatic color change in a liquid. These demonstrations probably required significant preparation if they were to work; I remember some duds, too, because things didn't go as planned.
2. Real world examples: I also remember enjoying having concepts (e.g. viscosity) illustrated through examples that I would encounter in life rather than in the textbook.
I strongly recommend doing a simple google search with these terms: active learning PowerPoint. You'll find all kinds of resources.
Cornell's Center for Teaching Excellence has a good, brief document that includes a brief list of other useful sources:
Bart, M. (2009). PowerPoint: Going beyond bulleted lists. Faculty Focus. Retrieved from: http://www.facultyfocus.com/articles/effective-teaching-strategies/powerpoint-going-beyond-bulleted-lists/
Clark, J. (2008). PowerPoint and pedagogy: Maintaining student interest in university lectures” College Teaching, 56, p. 39-45.
Gier, V.S. & Kreiner, D.S. (2009). Incorporating active learning with PowerPoint-based lectures using content-based questions. Teaching of Psychology, 36, 134–139. University of Minnesota Center for Teaching and Learning (2010).
Active learning with PowerPoint. Retrieved from: http://www1.umn.edu/ohr/teachlearn/tutorials/powerpoint/index.html
Speaking instead from my perspective as a student, my thought is this: in this large of a class, students don't necessarily want (or expect) to be personally engaged. There are far too many people for whole group discussion to be worth anything. When I entered a class of this size in college and found that my professor really desired us to engage with the entire class, I honestly just found it annoying.
One technique which worked a little bit was jigsawing, where we were put into smaller groups and expected to teach each other part of the material. This was especially effective when there was far too much material for me to learn on my own. I only participated when I knew that I was reliant on other students to fully cover the necessary material.
Another slightly effective (but still somewhat painful) approach that one professor took was to assign group projects with class presentations. At least this way, we could prepare in advance, which limits the potential for group-wide humiliation. I especially liked video projects, rather than live presentations.