Phoronix: Introducing The R5 Game Engine

With open-source game developers, the ioquake3 game engine is quite popular to use as a base since the Quake 3 / id Tech 3 engine is well-developed and famous thanks to id Software and then their kid generosity to open-source it when it reached the end of its commercial life. But there are many other open-source game engines out there too, including a new one that's just recently come about: r5ge, short for the R5 Game Engine...

http://www.phoronix.com/vr.php?view=OTM3Mg