Hi guys! I'm trying to plumb the group brain here. A friend of mine asked me for positive-future sci-fi story recs, and though I read a lot of science fiction, I'm having a heck of a time coming up with anything. This friend would prefer shorter reads, but for my own sake, I'd like to know about longer ones as well. I'm looking for something that portrays either technology or the future in general in a positive light...no dystopian society.

Help me, oh wise, AWers!