As part of each agenda item, state the amount of time allotted for it, the person responsible and whether the item is for information, discussion and development, or for action. Have a person responsible for keeping the meeting focused on the agenda items, keeping within the time allotted and writing up results. Circulate the agenda a few days in advance so people can prepare. Write up the results of the meeting and get it out to the participants. Have some fun at the meetings.
Laughter is good medicine.
Experiment with ways to enjoy yourselves while getting things done at meetings. It may take a little creativity, but escaping from the trap of deadly serious meetings will help everyone want to participate. And you team leaders, please remember to hold back a little in meetings and listen more. You'll be surprised at the good ideas your group develops. When you respond negatively, both you and the situation suffer.