I consider this to be really big, important news. Depending on how far the word can be spread and how well the community could try pitching in, I'd love to see the Linux game dev community grow as a result of this.
For those of you who didn't even know what AGS is, it's a game IDE for Windows. I've used it for years and loved it, and there was really nothing for Mac or Linux with AGS aside from shoddily-put-together game runtimes.
Anyways, Chris Jones, the developer of AGS, has decided to open up the source code to his editor, although the compiler itself is still closed (though it's noteworthy to mention that a new compiler can be swapped in to the editor technically. He's slowly open-sourcing it in stages to "test the waters" so to speak.
Anyways, the editor is written in .NET v2.0, and can actually be built with Mono, provided you have the Win.Forms libraries. One fellow managed to get it built and running on OpenSUSE natively.
Anyways, I just figured I'd post this as there's been interest for quite some time in porting the editor over to Mono, and eventually re-writing a UI in either Qt# or GTK#. If there are any Mono devs interested in trying to port it, write a new UI in a more Linux-friendly toolkit, or submit patches to aid portability, feel free to check out this thread.
Anyways, it's exciting to see this development come through. AGS is a great developer for the less-technical programmers (specifically indie game designers), and could aid in the development of many, many native AGS Linux games. Heck, the AGS community alone pumps out dozens and dozens of games every couple months, even a small fraction of that would be a huge boost to the Linux gaming community.