I always liked something like this. Useful set of groundrules for any meeting. Cover them at the top of the meeting or post them as a reference.
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.