If you are interested in doomsday scenarios check out the book, On the Beach. They made it into a movie too. I saw the movie before I read the book.
Stanley Kramer's movie On the Beach came out in 1959, and I went to see it right away. Because of its powerful message, the studio promoted it heavily around the world, even premiering it in the US, UK, and Russia at the exact same time. It absolutely terrified me. The film is a quiet, incredibly sad look at the end of the world.
After seeing the film, I read the original novel by Nevil Shute. As usual, there are differences. The director added a romance between Gregory Peck and Ava Gardner's characters that wasn't in the book at all. The author hated this change and complained about it constantly until he died the following year. Ironically, the movie's massive success caused millions of people to buy the book, making Shute a lot more money than his original publication did.
If you haven't seen it, the 1959 version is absolutely worth your time. It is a beautifully crafted, black-and-white film with fantastic acting. The musical score also does a perfect job of heightening the story's deep sadness. I'm such a big fan that I even own a restored Blu-ray copy of it.
As for the 2000 made-for-TV remake: it is not very good. They changed the story so drastically that the author would probably be spinning in his grave. The remake completely lacks the quiet subtlety that made both the original book and the 1959 movie so special, and the story really suffers without it.