This isn't exactly related to gaming, but Pixar Film Production have shown off their work using Linux + OpenGL in animating films. They say it can be used for games too and it's now open source.
A pretty good milestone has been achieved with the open source Vulkan driver for AMD that Dave Airlie has been working on with Bas Nieuwenhuizen. It can now run Dota 2.
Marek Olšák has recently sent word to the AMD mailing list that they have found a reason for some games performing poorly using Mesa. Another developer noted that a patch is already in progress.
After almost six months of hard work, we are proudly presenting you the marvelous Godot Engine 2.1. Just like 2.0, this version focuses almost exclusively on further improving usability and the editor interface.
For those of you using the RadeonSI driver for AMD graphics cards, you may be interested to know that a developer named Marek has sent in patches to significantly improve performance for Bioshock Infinite.
HaxeFlixel, a free and open source cross-platform game framework that was used in the creation of Defender's Quest is needing a bit of funding on IndieGoGo.
The Battle for Wesnoth is probably one of the all time great open source games. It's been around for a long time, it's well polished and now it's looking to get on Steam.