SP Summer gaming tips

So I'm gonna be back home with the parents over the summer working, and they only have crappy 3G mobile broadband which means XBL and PSN is out of the question so i wont have any MP game to dump my time into. 
 
I thought I'd ask the lovely GB community for tips on good games with a lot of time consumption possibilites without online for 360/PS3.  
 
Suggestions are much appreciated!
 
ps. feel sad for me that i wont have live/psn for 2 months :(

I just began playin Fallout 3 again, the game of the year edition is pretty long and great.

Without live, hmm. Grab yourself some JRPG goodness if you're into that kind of thing, go pick up something like Star Ocean, Lost Odyssey, Final Fantasy 13 (I hated 13, but, hey) or the like. 
 
Not into JRPGs? S'cool, get some Oblivion (yuck) or Fallout 3 (woot!) mebbe some Mass Effect 1 and 2. 
 
Or if you have a PC revisit some old classics, Fallout, Baldur's Gate, Icewind Dale, Planescape Torment, Outcast, etc.

Demon's Souls.  Probably a good bet as you will die a ton so that will definitely lengthen your play time.  Haha.

Fallout and Oblivion are pretty good, pretty obvious choices. 
 
Just Cause 2 kept me occupied for about fifty hours.  
 
Dead Rising might be good to hammer out, since the second's coming along later this year.  
 
But, honestly. You ought to just alternate between playing games and reading books. That's the way I used to spend my summers. Feels pretty fulfilling when the summer ends. 

Fallout and Oblivion i've pretty much played til death, FFXIII im about 25hrs into but don't really know if i wanna finish.  dead rising i never actually finished but still have so that could give me a few hours though, but i believe i quit cuz of frustration.
 
Demon's souls and Lost odyssey could be good picks though and maybe Lost cause 2 aswell
 
Thanks for the tips gents

Get The Saboteur. It's a riot! 
 
PS also, Mass Effect would probably be good, if you're into sci-fi. Fallout 3 also. These are 3 games that I will get round to eventually. I hope.

The basics which most people are going to shout out are Fallout 3, Mass Effect, Fable 2, and Oblivion.
 
Those are the must owns and if you haven't played them - now is your chance.  So, my post is from the perspective that you have, so check out the following:
 
What you want is an RPG.  Action games, FPS games, etc all end after about 7-10 hours.  For what you are looking for, they won't do.  You need RPG.  So, what games are good for RPG?  I'll break out some of my favorites by system.
 
Xbox: 
Star Ocean: The Last Hope (also on PS3, but cheaper on Xbox since it's older)  
Tales of Vesperia 
Lost Odyssey
Eternal Sonata
 
PS3
Demon's Souls - hardest game ever, but you will defintiely be playing it for a long time
Disgaea 3 - SRPG, never ends - awesome game
Valkyria Chronicles - SRPG
Final Fantasy XIII - better on ps3
Dragon Age Origins (also on 360, but I've heard PS3 is marginally better)


There you have it.  My favorites.  I'm sure I missed some, but I was going for the more obscure better rpgs out there.

Resonance of Fate...10 hours into it and still on Chapter 5, there's 16 chapters.  >.>

Thanks for the tips guys! It's helping out my summer plans out a lot 
 
I have played the must own games you mentioned @ttocs but from your list i've only played through star ocean, DA and FFXIII so thanks for the fresh advice!