I'm not a big fan of just repeating what I see on the Linux Game Tome so I'll be brief about these two: Warzone 2100 version 2.0.7 and X-Moto 0.3.0 got released. The former is a bugfix release (which was sorely needed) and the latter quite a lot of new features (notably hotseat multiplayer) and a new maintainer.
A few days ago I lamented about Adventure Game Studio not being available for Linux. I really should do my research before making such assertions... it is. Not only that, there's this groovy project to take all the hassle out of finding and installing AGS games - the Adventure Game Goddess.
Forget about boring hand tasks and enjoy the games ... One click: the game is downloaded, installed and set up. One click: you are playing
For those unfamiliar with the King's Quest series of games, it is probably the most promininent series of the genre. There's a lot of history and a lot of hardcore fans, many of whom were disappointed when Sierra was consumed by Vivendi Universal which eventually caused a rift with the lead author and the demise of the series after 8 games.
Some fans felt so strongly that they went on to create the The Silver Lining, a spectacular looking fan-made project to create a 3-game (or 3-chapter) continuation of the series. It was formerly entitled King's Quest IX before Vivendi Universal made them ditch the official affiliation. Sadly, The Silver Lining is closed source (but freeware) and Windows-only. I did lobby a while back to make them open source it and use OpenGL instead of DirectX but it fell on deaf ears. I must say, I was not enamoured by The Silver Lining tech demo either, whilst the stills look great the animation and scene transition was shakey at best, and there was a lot of aimless wandering around with very little to interact with. Still, it's just a tech demo, so I shouldn't be too harsh.
There's even a remake of KQ III (complete but Windows only and freeware) and KQ IV (in progress - although I'm not in the mood to read up on it but I bet Windows only and freeware). Project X looks interesting - produced by the same people behind the KQ III remake, Infamous Adventures.
I would do a KQ article with more information on and screenshots of each game, but it's too much freeware and not enough open source for my liking, so this little ramble will suffice and you'll just have to take my word for it that everything I mentioned looks at least ok or possibly even rather lovely. I reckon there are enough links to keep keen adventure gamers happy. ;-)