This clip points out what NOT to do when running a meeting. It's a funny clip--but what's not funny, is that meetings like this actually happen. You've probably experienced such a meeting yourself.
The biggest mistake a meeting leader can make is not planning in advance. It pays to have an idea of the expected outcome.
If expectations are to deliver brainstorm ideas, let the participants know this prior to the meeting.
If you don't plan, you run the risk of wasting the time of others.