If I didn't already own many of these games, I'd want this Humble Bundle. Warning: this bundle expires in only 16 more hours, so if you want it, get it fast!
Here are the ones I have, plus a bit about them. You can get all of them for only $8:
Long Live the Queen -
Basically a Choose Your Own Adventure story, although you get to
improve some of the main characters traits and abilities as you go
along, making it slightly more game-like than some of the other titles
in this bundle. The choices you make either allow you to survive a bit
longer, or they result in your death. It's surprisingly fun to play over
and over again, which is good, because dying is a very common
Analogue: A Hate Story - A visual novel (less game-like than Long Live the Queen).
You have to communicate with two different AIs in order to figure out
what happened to the final generation on board the space ship. I haven't
played this one completely through, but the portion I got through was
fascinating. Lots of family drama, plus extremely biased AIs.
Hate Plus - I haven't actually played this one yet, but it's the sequel to Analogue: A Hate Story.
- The visual novel in which you romance pigeons. The premise is wacky.
If that's not enough for you, there's an underlying mystery that you
slowly uncover with each playthrough.