CraftBukkit is a server mod for the popular sandbox game Minecraft.
Adding even more flexibility
Being free and open source, CraftBukkit offers you the ability to modify the way your Minecraft server is run. You'll be able to manage and create new Minecraft servers easily, which in turn will provide more flexibility when it comes to game customization.
As easy as .bat
After downloading CraftBukkit, move the craftbukkit.jar file to the directory from which you'd like the server to run on your PC. Open a text editor and type in the following:
java -Xmx1024M -Xms1024M -jar craftbukkit.jar
From there, just save the document as run.bat (not as a .txt, please note!) in the same directory you saved the craftbukkit.jar file in. Double click on run.bat, and CraftBukkit should start right up.
Customise your sandbox
CraftBukkit is a great way to customize your Minecraft experience to your own specifications.