Three dead men sitting at a table in a room. On the table, there are playing cards and a gun. What happened?
Two men shot themselves in the head, and the third one suffocated. The room is in a submarine lying motionless at the sea bottom.
The men had a gun with only two bullets. When there was very little air left, the men decided to gamble. The winners got the right to shoot themselves, and the loser had to agonize suffocating, accompanied by two corpses.