Indie PC Games?

Was just wondering if there are any fans of some of the odder/quirkier indie PC/Mac games out there?
I'll share a few of my favorites, but feel free to contribute - or maybe just discuss how you feel about indie games, positive or negative.
There's some really cool stuff out there, and I'm familiar with quite a few indie games (from Dear Esther to Gravity Bone), even though I may not have played them myself - so I'd love to talk and find new ones, if anyone's interested!

- OFF: An unusual little puzzle-and-turn-based-battle game with a great story and atmosphere.
- Undertale: This game is only availabe as a short-ish demo right now, but it's still a complete experience. It's similar to OFF in it's "meta" qualities (playing with the 4th wall), and has a really unique battle system. Depending on how you battle, you'll get different endings.
- Spelunky: a sort of dungeon-crawler with randomly-generated caves. It's addictingly fun, but also ridiculously frustrating - because death means starting all over, and almost everything in Spelunky works against you.
- Proteus: a very cool exploration "notgame" based on sound and visuals. It's not everybody's cup of tea, but I really enjoy it as a way to relax. (It does cost $10, however).
- Anything by Tale of Tales: more "notgames" that are closer to poetic experiences than traditional video games (although, trust me, they're not text-based). Some are free downloads, and some require payment - but if you're interested in this type of gameplay, I would definitely recommend checking them out.