So, I'm writing myself a MUD engine. Mostly as a learning experience, since it covers a lot of areas of game development without any of the complicated bits of needing to do graphics and audio. I'm doing it in Java as a totally, 100% from scratch codebase - because Java actually brings a lot to the table that is very useful for this kind of development, even though it's generally not as good for game development for various reasons. In specific the networking has been a doddle - see a future post - and I can imagine adding scripting in will be equally easy with the benefits of JSR-223.
I know full well that it's likely to not go anywhere, but it's an interesting project and actually covers quite a lot of ground that is best learnt by actually doing it instead of reading Internet posts. Plus there's not a huge amount of stuff on the Internet covering this type of thing. And if I actually do manage to get it up and running, then that's great :)