+ Hotline Miami. I loved it.

I've been big into indie games for a while. Some of my favorites include:

Super Meat Boy (obviously) - one of the best platformers you'll find

Broforce - An awesome co-op destruction platformer. It just got greenlit on Steam, but I think the beta is still online.

Limbo - absolutely gorgeous atmospheric puzzle platformer

Dear Esther - beautiful HL2 mod that is really more of an interactive story than a game. Some of the most visually stunning settings I've seen in a while, with a fascinating story line. You could complete this in one sitting probably, and it's a must-play.

Gone Home - another great interactive story type game. A first-person game, you play a girl who has returned home from abroad to find her family home completely empty. It's up to you to discover clues and figure out what happened. Beautiful little story and amazing riot grrl soundtrack.

Blocks That Matter - great puzzler

Jamestown - awesome vertical-scrolling co-op bullet hell 2d space shooter. Really fun with friends in local co-op.

Machinarium - one of the most popular and best indie puzzle games out there right now. It's a point and click adventure game with tons of puzzles on each screen, all of which are fun. But it's really the amazing setting and characters that make it - these little robots in a post-apocalyptic other-world. Very cool.

Braid - another classic. It's a platformer that allows you to alter time, which heavily factors into the gameplay and puzzle mechanics. Super cool.

Super Crate Box - super sweet 8bit arcade shooter

I should note that I discovered a large handful of these games (and many others) through the Humble Indie Bundle, a group that puts out bundles of indie games for pay-what-you-can, some of which goes to charity. It's really cool what they do, and a great way to discover new and classic indie games.