From Freeman Dyson, Inﬁnite in all Directions (New York: Harper and Row, 1988)—
At our institute in Princeton we sometimes organize meetings which are announced as Shotgun Seminars. A Shotgun Seminar is a talk given by an Institute member to a volunteer audience. The subject of the talk is announced a week in advance, but the name of the speaker is not. Before the talk begins, the names of all people in the room are written on scraps of paper, the scraps of paper are put into a box, the box is ceremoniously shaken and one name is picked out at random. The name picked out is the name of the speaker. The unbreakable rule of the seminar is that nobody whose name is not in the box may listen to the talk. This rule ensures that everybody does the necessary homework. The audience is ready to argue and contradict whenever the speaker ﬂounders. Anybody who has not given serious thought to the subject of the seminar had better not come.