If you were trapped in a room with one game..

[Aqualung]

Assassin's Creed. It'd probably teach me how to ninja my way out of that room, too..

 

[Osherai]

It would definately need to be an RPG Morrowind and Oblivion stole, nay, fulfilled weeks of my life =]
But considering I've drained them of all that can be done it'll have to be one I haven't played or completed yet so either Fallout 3 (new expansion coming soon ^_^) or The Witcher simply because getting used to it would take an age and the manual would become wikipedia to you =P

 

[Da_Schwartz]

Sims2. So i could lose myself in a pseudo similar life to my fomer one. And if worst came to worst i could then play it to trap other people in rooms and feel better about my situation.

 

[KenzS]

I'd pick WoW, if it worked without internet.

 

[Sporky111]

I would have to go with Fable 2. It really eats up the hours, and you don't even have to do anything specific; you could just play with your dog if you wanted.

 

[Valiance]

Probably something I could continuously improve at.

UT, or Q3A, or maybe Starcraft if I had the option of playing against good AI mods.

If I'm allowed to take mods and downloaded maps I currently have, Fallout 2, Diablo 2, and Warcraft III would be great choices too...

If it's vanilla, I'd probably have to go with UT'99, GOTYE.

 

[Railgun88]

Need For Speed Pro Street for the 360

 

[brenflood]

Galactic Civilizations 2 with all of the expansions. The game is different every time you play it and it has enough tech trees to explore to keep you entertained for a long while.