Ermmmm...if you want a nice somewhat indepth single player RPG...try Fable: The Lost Chapters.
I got the game a few months ago and I actually stayed up for a day to get somewhere on my character. I felt stupid for staying up, but I only did it because I had no idea what time it was.
...Yes..I really got into the game that much that I totally lost track of time.
I'm sure you could illegally download it, but I'd rather you buy it..it's a fun game. They're making a Fable 2 that I can't wait for.
Lost Chapters is for PC while normal Fable is for Xbox I beleive. The Lost Chapters has a few more golden questions(main missions) for you to do.