Kudos to Jeff Myers, who has set up a developer's mailing list for you adventurous souls out there who downloaded the Marathon 2 source code. From the post:

I have set up a developer mailing list for the marathon code You can subscribe by sending mail to listserv@3dgamedev.com with subscribe marathon_coding

Of course please replace with your actual name.

Soon I will also be seting up a web archive of the list discusions and webspace for projects/hostings if needed.

You'd almost think some people have been planning for this day. It may be a bit off topic, but any and all source code discussion is welcome on the forum (if traffic demands it, I'll happily set up a dedicated forum for it, too). If I get a few free days, I might just check out the code myself...