Spacecraft-GT is a project mainly written in C#, it's free.
Spacecraft GT is a new, Survival Multiplayer rendition of Spacecraft, the SpaceManiac Minecraft Server.
Spacecraft GT Spacecraft: Survival Multiplayer
Spacecraft GT is a new, Survival Multiplayer rendition of Spacecraft, the SpaceManiac Minecraft (http://minecraft.net/) Server. It is written in C#. It is soon to boast some neat custom behavior and a mob and physics engine written completely from scratch.
Spacecraft GT is licensed under Creative Commons Attribution-ShareAlike 3.0. You are free to share and remix Spacecraft provided you attribute the original authors and share any remixed code under the same or a similar license. See http://creativecommons.org/licenses/by-sa/3.0/ for full details.
Spacecraft GT is developed by SpaceManiac.
Want to find out more? Check out the Spacecraft GT wiki on Github: http://wiki.github.com/SpaceManiac/Spacecraft-GT/