Forever - until the end of time... The universe apparently is experiencing increasing entropy and distribution of mass and energy (really two aspects of the same thing), and eventually will just become one vast uniform energy field...
The way I look at it [turning head sideways, letting tongue hang out], the universe has a choice:
a. Just hang around being everything, forever (boring!)
- or - b. Condense into physical matter, spark organic chemistry, start evolving stuff, develop consciousnesses, and enjoy the story.
If you were the universe, which would
you choose? Even we do (b.), whenever we watch a movie or TV show, or read a book. The content's already there (it's not limited by time), but it's exciting because we experience it in a linear fashion.
If the universe can become everything around us, clearly it can do anything. So even if it plays out and becomes a uniform energy field, why assume it'd stay that way for long? Who knows what's next? Maybe next it'll be a Space-Saving universe, without tenkeys.
Time will probably continue to run, although there will not be anything left to measure... Under those circumstances, we could be logged in forever, but there would no means of measuring it any more.
If nothing ever changes, how can time exist as anything but an abstract concept—sort of like the idea that my wife liked me once?