**WARNING - CONTAINS HUGE SPOILERS FOR 'THE DARK KNIGHT'**
The Joker has wired two ferries up with explosives (that cannot be defused). He announces that in twenty minutes' time both will blow up - unless either of the ferries uses the supplied detonator to blow up the other, in which case the remaining ferry will be allowed to go free.
One ferry is full of civilians (including children). The other full of convicted criminals. They have no way of contacting each other or anyone else.
If anyone attempts to leave the ferry - both will be blown up immediately.
You're on the civilian ferry...
What do you do?