One of my favorite experiences in the PAX 2013 Indie Mega Booth was Klei Entertainment's Incognita. The developer has taken elements of turn-based strategy and blended them with the extended roguelike play of FTL. Put simply, we kind of liked it.
You can see what all the fuss is about right now, as Klei is offering up a paid alpha. The $ 16.99 entry fee ($ 19.99 with soundtrack) gets you access to the current build of the game, with beta and full release coming later when available.
I'm not sure how I feel about the concept of paid alphas in general, but this one has me very interested. $ 16.99 isn't a lot to ask if you're interested in watching a game develop over time.
Klei's track record (Mark of the Ninja, Don't Starve) also offers confidence that a final version of the game will happen when ready and that it will be quite good. If you've ever considered buying into a game at the early playable stage, this is a good place to start.