Alright guys/gals, this one is extremely hypothetical but in a sense does have something to do with us and humans as a species.  Granted we don't destroy ourselves or are wiped out by aliens, etc., that is to say that we survive to see the day when all of the energy and matter in the universe starts running out, what will we do? In a more scientific sense: How may entropy be reversed?  I realize technologies would be incredibly different than now.  It's like comparing rocks to missles.  Isaac Asimov wrote about this in his famous short story "The Last Question".  If you are interested you can find the full text here, it is a very short read:

http://www.multivax.com/last_question.html