If you are a developer, please build MegaGlest on your own and get in touch to contribute (or post your patches on the forums).
the source code may be Open Source, but the game and the media it consist of have their individual licenses and copyrights... do realize that only the sourcecode is yours to use freely (if you abide by the ZLIB license, see below), while the media is not. You can't simply redistribute the entire package with your modified files, as the majority of game media is not yours to use freely (it is made by many authors with a variety of licences and copyright restrictions). Unless you have explicit permission from the authors, or the readme says explicitly "may be used for any purpose" or similar language, it will be illegal to include in your standalone game based on the engine (you may not assume that just because a file has no explicit license, that it is free of copyright). Therefore, if you wish to produce a standalone game, be prepared to make many of the maps, models, textures, sounds etc from scratch yourself.In this sense Cube 2: Sauerbraten is similar to games like Quake (its code is Open Source, but its media is not), it is a game that is meant to be added to, not copied and used as a template. Sauerbraten is not meant to be a quick game creation kit, it is a game.