I came across this page by accident. It's a site called Vault52, and it seems to be a community site that also has a Fallout MUD in progress. The home page proclaims the site is "built completely in flash and java", but don't let that put you off. Doing some searching on the site came up with this:
Vault52 is the latest project of Philip Luppens.
The goal is to make an online adventure/rpg/simulation
in a post apocalyptic setting. We are currently
working to create a bigger world, with more terminals,
computers, rooms and content.
It is important to know that this is a non-profit
project, being created in our spare time only.
We can use any support you can give us. So please,
if you think this project is worth a look, please
tell your friends.
The site then links to somewhere called Vaultnet.net, which has a dead link on the main page but a forum that was recently updated with screenshots of an upcoming Post Apocalyptic RPG.
I'm not sure if this is the same as Vault52.net's online game. I just
found the whole site a bit bizarre, especially since I'd never heard of