Interpretation of AssaultCubes license
It seems a LOT of people here are very confused as to what AssaultCube's (and Sauerbraten's) license actually is. I will make a vague attempt to spell it out in simpler terms.
The source code, and ONLY the source code (ONLY the files in config/ and source/src/) are under the Zlib license. This means you may reuse that code, but you may NOT claim you wrote it, or remove our copyright notice from the code. source/enet also carries a similar MIT-style license, that basically just says don't remove the copyright notice, so same difference.
EVERYTHING ELSE IS UNDER *DIFFERENT* LICENSES THAT, IN GENERAL, DO *NOT* GIVE YOU THE RIGHT TO FREELY REUSE THEM. The models, the textures, the maps, and whatever other media. Look in docs/package_copyrights.txt for more clarification. If there is a license.txt or readme.txt within a specific directory that gives other licensing terms, then those licensing terms apply ONLY to the files within that directory and its sub-directories. If some directory does not carry any explicit licensing terms, or it is not said in docs/package_copyrights.txt what rights apply to that directory, then you must assume you do NOT have the right to redistribute those files at all, except as part of the entire AssaultCube distribution. SOME files within AssaultCube may actually be reused, but ONLY if the license attached to those files EXPLICITLY says so.
The entire AssaultCube package MAY be redistributed, however, some of the files within it carry a "FREE FOR NON-COMMERCIAL USE" clause. What this means is, you can NOT sell the AssaultCube distribution for profit, or this would violate the individual licenses, UNLESS YOU REPLACE all those files.
Originally by Eihrul