LOGOS is a new sci-fi themed collectible card game based in Second Life, and it looks pretty damn cool:
"The game is played by wearing a HUD that adds an interactive gaming interface to the view of the player," Oni Horan, who created LOGOS with Darien Caldwell, tells me. "To play the game you have to collect cards and put them together to make a good deck..." Combat is resolved via the LOGOS heads-up display: "Two players can start a battle with each other anywhere they like and are rewarded with experience points which will get them free cards." (You can find other players online by joining the official group. Also, if another player wearing the game HUD comes within range, you'll hear a helpful chime.)
Beyond the game, LOGOS has some pretty interesting back-end technology: "We are using Google App Engine for our game database and for all in-world/web communication," says Oran. He thinks the free service can be a boon to other Second Life developers, "allow[ing] us to try such a risky niche project while still being able to guarantee its longevity." Looks like Second Life's Combat Cards has some healthy competition!