As announced last month on the Valve for Linux blog, the developer of the popular gaming platform "Steam" has started an external beta test of the new native Linux client involving up to 1000 volunteers. Initially the test is restricted to one of Steam's games ported to Linux and the Linux distribution Ubuntu 12.04 or later versions thereof. In order to apply for a tester position you need to complete a survery on the Valve web site.
Besides the Steam platform itself, the company has also been working on porting some its games to native Linux. Through the company's CDR database, gamers have been able to compile a collection of games that appear to be ready in native Linux form. A CDR web query for games with Linux support currently yields a list of 19 titles, including Darwinia, DEFCON, Eversion, Serious Sam 3: BFE, Amnesia: The Dark Descent, Dynamite Jack, Crusader Kings II, and Cubemen.
Valve engineers managed to optimize the Linux Steam client, Open GL, and various drivers to the extend that games now run faster (more frames per second) on Linux than on Windows. Keep up-to-date on the latest developments on the Steam Linux blog.