How would YOU end the world?

[Pip Boy]

Bob the Mercenary's "catastrphic global meltwdown caused by laser" tabloid thread got me thinking. Even if that particular machine would never actually cause something like the end of the world, the Earth exists in a very delicate balance. If it tilts a little too much, END OF ALL LIFE AS WE KNOW IT. If the moon weren't in that particular rotation/position/size, END OF ALL LIFE AS WE KNOW IT. If we were about 10% closer to or farther from the son, END OF ALL LIFE AS WE KNOW IT. Hell, at any given moment a quazar could just come out of nowhere and fuck our shit up.

Given, say, a few billion dollars to build whatever crazy contraption you would like, how would you herald the end of the world as we know it?

What'll it be? I'll concieved tampering with the earths bowels results in geological instability? Wheather machine accidentally cause A category fuck you hurricane? Slow down the moon's revolution just a bit so it'll come slowly crashing down on top of us? Lets hear it.