Minecraft

[Whacker]

If you do, make sure you install one of the better server admin tools.

http://www.minecraftforum.net/viewto...f=1012&t=23483 Llama mod

or

http://www.minecraftforum.net/viewto...f=1012&t=24629 MCAdmin

Edit - You'll also want to greatly expand the server world map by exploring so that it pre-generates the chunks. If people go beyond already explored boundaries, the server will generate the new land and this can really bog it down big time. Lastly you can use stuff like MCEdit to import your existing structures, etc.