I heard about this game "Digital: A Love Story" by listening to Giant Bomb's GOTY podcasts. It's a simple little game, and it's not technically proficient, but it's ... poignant. I'll can't say much more about it, as that would ruin the entire point of playing it, but it'll leave an impression, unless you're a cynical bastard with a heart of ice
If you want to have a look at it, it's right here. It's incredibly simple, and at about 56MB it shouldn't put a dent in your hard drive, plus it'll run on Windows, Mac and Linux, if that's your flavour. Also, it's free. I highly recommend checking it out.