Hydrogen Minecraft Server
The Hydrogen Minecraft server is no longer in operation. Here's the Reddit post explaining why. However, the server is once again accessible at tuonen.servegame.com, and a new Survival is in place. Souhait and VIRUS are also accessible in Flatland.
You can download the Souhait campus, with the server files necessary to run (26.3 MB), or the card game used once (Excel file).
Otherwise, you're probably looking for:here.