Age of Ultimacraft is a standalone Minecraft server that features a world based on Britannia, and which draws numerous features and rulesets from Ultima Online. It supports guilds and PVP, and includes (at least) areas based on Yew and Skara Brae (the latter of which features in the screenshot above).

The Age of Ultimacraft team seem to be pretty active on Twitter, so you can follow them there for more updates. That said, their website also does contain a lot of additional information about the server, at least if French is a language familiar to you.

And yes, of course, there’s a brand new project entry for Age of Ultimacraft here at the Codex.