This is a pretty simple game: answer the last player's "What could possibly go wrong?" statement, and then make on up of your own, like so:
1P: What could possibly go wrong with gunpowder as fuel?
2P: KABLOOIE!!!
2P: What could possibly go wrong with dictatorships?
3P: Take a look at Nazi Germany, 1940s, and North Korea, right about now.
Here's the first statement:
What could possibly go wrong with flying Humvees?