As long as we're touting other games...
Unreal Tournament, using the new Unreal Engine 4 announced development commenced on May 8th.
The player community is invited to participate in decision-making discussions in the forums and, for $20/month can get full access to the design tools
and source code as it's developed. The community will be participating in playtesting the game from alpha, and when it's released it will be free. Not Free to play but free!
When I get back to work I'm thinking about subscribing to the development tools and trying a few things.