Endless Sky is one of the best free games that I have ever come across. It has some issues, such as it still being in development, but overall it's still an awesome game. One of the perks is that it's easy to mod and add your own content and such at github.

http://store.steampowered.com/app/404410/
https://github.com/endless-sky

 

I've played a bit and it seems alright. The default control scheme is donkey balls though.

I'm not sure if I'll reconfigure the keyboard controls or just use joy2key/xpadder/something similar.

 

Oh man, Escape Velocity. That was the first game I ever played. I loved that shit so much.

Really not my thing anymore, but I might have to play it just because nostalgia.