In case you were unsure about the Endless Space free weekend...

...you now have an extra incentive to take advantage of it.

http://endless-space.amplitude-studios.com/Games2gether/G2G-Community-Rewards

Basically, if you like the game, you'll have helped get extra, free content for whenever you end up buying it. And if you don't like it, you'll have comfort in the fact that you at least helped a community.

Edit: Forgot to mention, you don't need to do anything on the site, you just need to accept a dialogue inside the game, as soon as you start it.