I was watching K-PAX earlier (on More4), and the theory offered at the end was quite disturbing: "The universe is expanding and contracting over and over, making time go forwards and backwards, so that every mistake we make in our lives is a mistake we'll have to repeat every time the universe expands again. Over and over and over and over."
If the tedious eternity of immortality seems awful, what about repeating whatever the current moment is over and over again forever? :(