I'm no scientist, but after thinking about it, I have come to this conclusion:
The universe will end (ironically) in the "Dark Age", where all matter has been replaced/consumed by black holes. This will continue for a ton of years as the black holes degrade, particle by particle (they actually do this FYI), and the matter will scatter (ADVENTURE RHYME), and eventually culminate at one point in the universe, (after all, matter has an infinite time to do this), constantly pulling itself together, creating heat until for reasons unknown, it explodes. Into a big bang.
But I'm not a scientist, so I'm sure a proffessional could point out 30 flaws in this, but it makes me happier :D