What would happen if we knew it was the end of humanity?

I got this idea after thinking back to a book I read several years ago, that was recently made into a movie.

The Children of Men is a book/movie in which the human race can no longer produce offspring, for an unexplained reason. Thus, mankind has come to the realization that within 100 years, the human race will cease to exist. There is no future. The book was interesting to me (and the movie moreso) because it presented an interesting situation, and some interesting potential reactions to it. Namely, mass depression, government sanctioned and assisted suicide, a loosening of morals and inhibitions, war to the point that only several small countries remain, religious awakening, etc...

So what do you think would happen if we knew that within 50 to 100 years, we would all die off no matter what? What if there was an emergency news broadcast, worldwide, in which we were told that within 50 years, a giant comet would strike the sun and wipe out our solar system? And there is absolutely nothing that can be done.

War? Perhaps world peace, finally? An abandonment of science? A return to spirituality? Suicide? Drug use? Lack of desire to live?

I don't think I would go to work anymore for one...No point in that really. I can't imagine anyone doing any sort of research would want to continue either.

I'd like your opinions.

I for one would just riot.
Wars would flare up everywhere, law enforcement would cease to exist. All power and water would stop.

It'd be great fun.