Dear Esther, a unique first person adventure game powered by Valve's Source Engine, will soon be released as a native Linux client. Currently the company is seeking out testers to try out the Linux port.
Back in March while many were still doubting my claims of Source/Steam coming to Linux, I mentioned a native Dear Esther port was being looked at. Being tweeted recently by Robert Briscoe, one of the artists involved on the game, is that they're looking for testers.
From Twitter: "Linux/Ubuntu users, we need testers! Message me with your details if you're interested in helping make Dear Esther on Linux a reality!"
Dear Esther is self-described on its website as "a ghost story, told using first-person gaming technologies. Rather than traditional game-play the focus here is on exploration, uncovering the mystery of the island, of who you are and why you are here. Fragments of story are randomly uncovered when exploring the various locations of the island, making every each journey a unique experience."