You may already be a winner!
Actually, probably not. Your chances of winning the Publishers Clearing House Sweepstakes in a given year are considerably smaller than the probability that a large meteorite will collide with the earth and kill you and everybody else on the planet. Kind of depressing when you think about it.
Devastating meteorite strikes capable of causing widespread extinctions are estimated to occur about once every 30 million years. I won't get into a detailed discussion of whether these are periodic or purely random. (A very interesting recent theory proposed by Lisa Randall and Matthew Reece postulates that meteorite strikes are triggered every 30 million years by the Earth's passage through a disk of dark matter). Also, I am using "meteorite strike" here as a shorthand for any rapid mass-extinction event -- a nearby gamma-ray burst could also kill us all, as suggested by my erstwhile collaborator, Adrian Melott, and his co-workers. But let's say for the sake of argument that your chance of dying from a meteorite strike in a given year is about 1 out of 30 million, which works out to about 1 out of 400,00 over the course of your entire life.
And what about the Publishers Clearing House Sweepstakes? According to their website, your chances of winning the grand prize are 1 in 1.7 billion. That's "billion" with a "b". Calling these odds astronomical would be an understatement -- they are really cosmological. If you entered the contest once a year, you would need to play for a considerable fraction of the entire age of the universe to have a good chance of winning. So don't hold your breath. Actually, you might want to hold your breath, because another mechanism proposed for mass extinctions is the release of hydrogen sulfide into the atmosphere.
A happier note for those afraid of flying: if you fly only a couple times in your life, your lifetime risk of dying in a plane crash is actually smaller than the risk of dying from a giant meteorite strike. Every cloud does have a silver lining.