Easy!
I have absolutely no social life whatsoever.
I dunno, it doesn't take all that much time, I spend most of my evening playing chess when I'm not doing homework. Also I do most of my tactics problems in the morning before class. I guess it's just time management.
Somehow I also find the time to work out 3 days a week and keep my girlfriend content. I'm superman! Also I'm thinking I might start learning the piano soon.
It pays to have no friends. 
Oh and as a minor update I've finished "Reassess your Chess" and have moved on to doing the problems from the Reassess your Chess Workbook. Silman suggests that you write all your solutions down in a notebook as you do them and then go over all the solutions after you've completed the book. I've started with this idea and it's pretty cool. After I finish Neil McDonald's "Giants of Strategy" I think I'll either go through "50 Ways to Win at Chess" by Steve Giddons or "Understanding the King's Indian" by Mikhail Golubev. I haven't decided which yet...probably Giddons.


Eric,
How do you find the time to do 100 tactics problems daily? Plus 1 chapter from Reassess your chess and several games from McDonald's book?