Give Me Back My Son
Players in a circle, one in the middle. The one in the middle must approach players one at a time and yell "Give me back my son!" in the over-dramatic style of Mel Gibson in the movie "Ransom." If the player on the outside of the circle laughs, then that player becomes the player in the middle.
To practice emotional commitment, even when doing something silly. And to make your teammates laugh.
Many people try to make this warm-up into more than it is by responding to the line, or delivering the line with another emotion. This may undercut the simple beauty of the warm-up.