Who doesn't love to hear, "I declare the meeting adjourned!"? The Robert's Rules motion for adjourning a meeting is simple but essential for almost every meeting.
Situations in which adjournment can take place without a motion are
When the hour adopted for adjournment has arrived. The chair announces the fact, and unless you or someone else is pretty quick to move to set aside the orders of the day, the meeting may be adjourned by declaration.
When you reach the end of the agenda. The chair may just ask whether there's any more business; if you don't speak up to make that motion you've been thinking about, and if no one else speaks up, the presiding officer can declare the meeting adjourned.
Another instance in which adjournment doesn't need a motion is when some emergency or immediate danger makes hanging around for a vote a really knuckle-headed thing to do. For example, if there's a fire, your presiding officer should just break the glass to set off the alarm, and then declare the meeting adjourned to meet again at the call of the chair.
A meeting isn't adjourned until the chair declares it adjourned, no matter how loud the "ayes" ring out when the vote is taken.
The motion to adjourn is straightforward and simple. It comes in three basic forms:
Adjourn now: "Mr. President, I move to adjourn." Adoption of the motion closes the meeting.
This form of adjourn is the only way in which the motion may be used as a privileged motion (meaning it can be made while other business is pending).
Adjourn to continue the meeting later: "Mr. President, I move to adjourn to meet again tomorrow at 8 a.m." This form sets up a continuation of the current meeting.
Adjourn sine die (without day): "Mr. Chairman, I move to adjourn sine die." This form adjourns the assembly completely and is used to end the final meeting of a convention of delegates.
Although the second two forms are not privileged (meaning they're only in order as main motions and can only be made when no other business is pending), the rules of procedure are otherwise the same.
Between the time the motion to adjourn is adopted and the chair declares the meeting adjourned, any one or more of the following actions are permitted and in order:
Providing information about business requiring attention before adjournment
Making important announcements
Giving notice of a motion to reconsider a vote that took place at the meeting
Moving to reconsider and enter on the minutes in connection with a vote that took place at the meeting
Giving notice for any future motion that requires previous notice to be given at a meeting
Moving to set the time for an adjourned meeting
The privileged motion to adjourn
Can't interrupt a speaker who has the floor.
Must be seconded.
Can't be debated. (However, if the motion specifies when adjournment will occur or sets a future time to which the group will adjourn as a continuation of the current meeting, that aspect of the motion can be amended and debated.)
Can't be amended.
Must have a majority vote.
Can't be reconsidered, but can be renewed if any business has gone forward after a motion to adjourn has failed.