I really enjoy Good Old Games, as they bring a lot of older titles to the PC in a way that newer machines can generally run them easily enough. Well, GoG has a nice freebie for the next couple of days - the original Fallout is free. You can find it here if you are interested.
I figure it's worth checking out since creating an account there is free. I know when I first signed up, I got a couple of freebie games that were pretty 'meh', but Fallout's still pretty solid today, and GoG has done other giveaways over the last year as well.