Fallout 3 is legitimately my favorite game of all time.
No game beats it in my opinion.
Summer between my 8th and 9th grade year (i think) I had to stay at my grandmothers house with my mother almost the whole summer because my grandfather had recently passed and we were there to keep her company. She had no internet there, so the only xbox games I could play were single player games.
Needless to say, I played the forget out of this game.