eventually, the universe will end, and before that, the sun will explode. Although I think that in however million/billion years it takes for the sun to get to that point human will have left our solar system, and probably our galaxy, so when the universe ends, so will I. Just make sure that you're on the whatever deep space mission you can be, so that you aren't near any exploding stars or anything like that.
Also, after about a billion years, time would start to go by quite quickly. You eventually have no concept of time, because it would mean nothing. Whole civilizations could rise and fall in days to you. It would be... interesting.