what happened?

You start by telling the situation:
"A naked person lies in the middle of the desert holding a broken match in his hand. The person is dead and there are no footprints around him."

The group has to find out what happened to the person by asking you yes/no questions.

The story:
Three men were flying over the desert on a hot air balloon. Suddenly they started to fall down. To make the balloon lighter they have threw away all their stuff and their clothes. But that didn't help. So the men decided to draw matches, the one with the short match would have to jump off the balloon to save others.

You can make up different situations using the same principle.