Joining our Minecraft server is easy!
Just download out custom launcher http://underdone.org/minecraft/underdone%20minecraft.zip
Extract the folder to somewhere (like your desktop) and run the Launcher.
(Use Administrator privileges if you get any issues)
Click Underdone on the main menu and click Launch.
Online Map: http://188.8.131.52:8123/
Post any issues in the forums.