Now closed down. Thank you!
US: ancardia.us.to
EU: ancardia.uk.to
To play: SSH in with username adom and password adom, follow the prompts to create a new account, then SSH in as your new user. The full readme is at http://ancardia.us.to/ .
Windows users can use PuTTY to SSH. Please, see the README section about configuring PuTTY optimally. Mac users need to check "Use bright colors for bold text".
The server includes most versions of ADOM, social features like spectating, and game mods like ADOM Sage. It can be accessed from anywhere with an Internet connection, and it doesn't matter if your Internet or battery run out.
The code for running your own server is on GitHub. The INSTALL is long, but it's easy.
18-Jan-2013: I got four months of an EU VPS for free, so I've set up ancardia.uk.to. This server is actually in Amsterdam, NL but .nl.to wasn't a choice and I wanted symmetry. The accounts and hi scores are separate. The code base is also slightly better (one day I will switch the US server). The provider is selling VPS's very cheaply, so I'm not sure how it will keep up with demand, reliability, support, or price, but it seems good so far. Once my free months are up, if the VPS is deemed sufficient, I'll switch the US server to the NY datacenter from this new provider and end up saving ~$3/mo even while running two servers.
13-Apr-2013: The US server moved to New York. DNS changes have been made but you may encounter some delay picking up the change. The new IP is 198.211.110.96.