I always liked something like this.

Meeting Ground Rules

• Respect Your Colleagues!
• It’s ok to disagree, respectfully and openly. Silence is consensus, please speak up with concerns!
• Listen as an ally and with an open mind.
• Only one person speaks at a time.
• Honor the limitations of time, speak concisely.
• If you state a problem, try to offer a solution.
• If you have a comment a bit off topic but you want addressed , write it down for a possible follow up meeting.
• Hold questions if it is a presentation, make sure presentations offer pauses for questions.
• Please put cell phones on vibrate or turn them off.
• If you must take a cell phone call, please leave the room quietly.