The idea is that two people are in a hot-air balloon, it's losing height and looking as though it will crash into the jungle with nasty poisonous frogs, evil squawking parrots and no doubt dinosaurs like in one of those 'lost world' movies. There's no fuel left - and the only ballast is the passengers.
What the people concerned have to do is to justify their existence in a limited length of time, and the one deemed to be worthy enough to survive will do that - no doubt just long enough to embark on another perilous cross-Amazon journey in a leaky balloon with insufficient fuel.
For the other? Well, 'plummet' is a good word that sums up the situation.
C'est la vie - or not, as the case may be.
We used to play this at Speakers Club many years ago, and the time you had to work out what you were going to say was the time it took you to walk up to the lectern (of course, I had a bad leg, which explained why I ended up with more time to prepare).
You can use any strategy - after all, it's life or death - be funny if you like, tragic, tell us about why you deserve to live - or why your fellow passenger deserves to plummet - how you do it is up to you. I stress it's not a popularity contest - or it just might turn out to be if you wish to clutch at that straw. As for me, I'm going to try to make self-deprication a virtue and go for the sympathy vote.
Who wants to play? If we can get 8, all well and good. 16, even better. It's a knockout.
Edit: Look at me - can't even spell 'self-deprecation'. I'm a hopeless case.