I want to say I'd head for D.C. with a case of dynamite and the hope that congress is in session.... More likely I'd get stoned and try to get laid one last time.
It's kind of funny, I know perfectly well that I'm going to die one day but it isn't something I think about, but if I knew the date I was going to die on, even if it was way in the future I think it would weigh on my mind constantly. I guess some ignorance is bliss...