I've been playing with Blender since March. But I didn't even know it had a Python CLI! :) I don't expect to master it until the end of the year. One of the nicest and fun pieces of open source code I've used. The interface is a pig to master if you have previous experience in 3DMax/Milkshape/Unreal, but when you do get used to it you start to love it. They recently reactivated the games engine which is part of Blender too, version 0233, I haven't looked at that yet. Also sitting on my disk is a folder called Crystal Space A friend of mine in Canada put me onto this a year ago, and he is in a team developing a game with it. So far I ran the demos and wrote a 'hello cube and light' world. Crystal space looks very impressive in scale, its also very open ended programatically the demos show HUD and menu interfaces, particle systems and all sorts of goodies for the games developer. Perl and Python are usable here. Let's not forget Gimp for 2D, which is also Perl scriptable, perfect for procedural textures.

Games development is rather costly in time and skills. It's rare for one person to be capable of doing it all. The last mod project, SAS I was involved with sucked up 60 man-years of labour at least! You are very very lucky in this world if you happen to be a great 3D modeller, and a good coder, and sound designer, character animator, voice artist, musician, texture artist, level designer and tea maker. Thats what you need to make all the content. Skilled coders who start out to write a game usually make a nice engine and thats where it ends, they never reckoned on the cost of the content (one impressive exception is WoutersCube). I'm guessing that with modern games the content outweighs the engine development by a factor of 3 to 1 at least. The perfect solution imho is to make a framework that is so extensible that the players write their own content. Can't you already do that in Sims in a weak kind of way? I confess not have gaming experience with MM, I tend to prefer FPS realtime and strategic combat (Operation Flashpoint) which are limited to 30 or 40 players and a few tens of square kilometers space. Once a game like this gets released the community write the content. Presently OFP 3rd party content dwarfs the original Bohemia Studios release. The reason I think OFP and Unreal are successful, and why I stay with them, is that despite being proprietry software they are very open in releasing development tools and documentation to the community (plus there are many fanatic gamers who reverse engineer and document too). For open source I think there is a definite gap for a killer game, proof of concept of integrating all the above tools. I'm sure this team already exists if you look for it. Good luck, If you do find out let me know, I'd be very interested.