As a wife and mother of two children, it is sometimes hard to get a moment alone. I have discovered a few ways to get some peace and quiet. Let me share them with you:
If it is just after a holiday, announce you are taking down all decorations and putting them away.
Tell the family its a seasonal cleaning time, have rubber gloves on for authenticity.
Storm into the room with annoyed look and say you are glad they are all gathered as you have some things you want to discuss about division of chores. (Beware: this can cause a stampede so have clear exits)
This last one is somewhat dangerous as it can create a credibility gap, but announce to family that you have just made a new dinner for them to try, that you think they will hardly even notice the spinach and asparagus in the meatloaf.