Penumbra: Overture

A First-person horror adventure with a unique physics system. one of the more original games coming to linux this year. It's a 3-episode game. You can get the linux demo beta over here and submit any bugs you get. Here's a video demonstratic how awesome the game's mechanics are:

Gate88

This game is like 3 years old now, but it's free and it's maker just won 2 IGF awards for his next game EverydayShooter. Also, i just got to try it a short while ago. It has awesome music. an original concept. and Multiplayer support. It's an RTS-Arena shooter fusion that's fun to play.

Misc.

• Gish (the most fun commercial linux platformer I ever played.) is getting a sequel. check the concept art at cryptic sea.
• The PCSX2 are making progress with the linux version. Right now tons of games are already playable with the awesome new emulator. Winning Eleven 11 Works!!!

p.s Yea, I'm the first one to embed a youtube video in eglug. beat that :P