Naomi has a brilliant post on the care, use, and feeding of committees, a form of organization highly prized in academia. It is also the way things get done on independent school boards and community organizations.
The ideal committee meeting should run no more than an hour and a half before a break, and that's assuming a committee which is taking up a whole slate or urgent issues: the ideal meeting focuses on one issue, reaches a decision, and ends slightly ahead of time with everyone feeling good about their participation.
This last is probably the element I see ignored most frequently by incompetent committee chairs: even when they do not turn "dialogue" into a verb (see Gandhi, infra), they labor under the impression that a committee meets in order to facilitate communication or some such malarkey. If you just want to chat with people, you call it a party and you bring a lot more food and drink, okay? A committee meets in order to discuss and ultimately make one or more decisions. These decisions will be made by the people who actually show up, which is why committees work at all. (The history of the U.S. Constitutional Convention is particularly instructive in this regard.) Meeting after meeting of decision-less discussion, however well-intentioned, will sap the life from any committee. Indeed, an undeclared filibuster is a brilliant way to stop the committee from accomplishing anything, which is presumably why a call to question cannot be debated or amended in Robert's Rules of Order.
I learned to be a good committee chair from Dick Otter, who is a stockbroker and tireless volunteer. He was the chair of the Yosemite Fund for many years. From him I learned the trick of timing the meetings, and of carefully cultivating discussion (not too much, not too little.)
Another thing I've learned from The Girls' Middle School is to have a balance of power within the committee (or board). If one person has too much, it's like having a flat tire, things run as well. Also I learned from Kalamu Chache, who is a poet, a community activist, and a stand-up woman, how not to let one person subvert a meeting. I think I had to watch her do it to have the nerve or the skills to do it myself.
Tom Malloy and Dyane Matas, in their roles as Chair of the GMS board, introduced me to the concept of setting out a theme for the year, and planning what topics will be covered in which meeting. These two steps have made our work much more productive, I believe.