The Autumn Sale on Steam has begun.
It goes by the name "Steam Exploration Sale" and starts today, November 26th 2014 and ends on December 2nd, 2014.

Watch out, Friends of Point-and-Click-Adventures: the complete Trilogy of Deponia is now available on Steam also for Linux!

Update: The day has come: Dead Island is right now available on Steam for Linux (unfortunately not in Germany)!
If you already own the game for the Windows-Platform, you can start your download right away.

The Website Gaming on Linux has more Informations on this Port: it is native and not some kind of Windows-Wrapper like eON oder Wine.

The Game-Classics from Sid Meier Colonization, Pirates and Covert Action are now available for Linux on Steam.

Costume Quest 2 is now available on Steam for Linux.

Description:

A sequel to the popular Halloween adventure from Double Fine Productions!

Pandora: First Contact, a turn-based 4X-Game set in Space is now available on Steam for Linux.

Description:

Pandora: First Contact is a science fiction 4X turn-based strategy game on a planetary scale. Our Earth has been exhausted and colonial attempts on other planetary bodies have been in vain. Finally, after decades of exploration, an interstellar probe has brought promise of a new world many light-years away.

Flockers, the new game from the makers of Worms, is now also available for Linux on Steam.

Description:

New from the creators of Worms, Flockers is a modern day take on the classic A to B puzzle genre with a generous helping of dark humour for good measure.