Hey, hey, hey, one more for the road. Pretty sure we've seen this one already, but in case you missed it the first time. Today, for you:
Endless Space Collection will be free at Humble until September 14th at 10:00am Pacific Time. Just follow the link above, log into your Humble account, make sure you are subscribed to their newsletter, then click the green 'GET IT NOW' button. This will get your a Steam key for the game.
Have a look if interested and enjoy.