CircleMUD was a popular piece of server software for running a MUD, and it came with a sizeable virtual world (which the admin could modify/append to customize their fantasy world.) It would be pretty handy to use parts of this data if you were creating your own virtual world for a text adventure game, but the format of CircleMUD's data files is kind of obtuse and not amenable to manipulation.
So I wrote a few scripts to convert these files into a single XML file which is 4MB when unzipped. You can parse this file and modify it to suit your needs. It contains 1979 rooms across 30 different areas (called zones in the file), with 46 shops and 569 different "mobs" (mobile objects, which are the monsters and NPCs). There are 678 different types of objects, including 116 weapons and 154 types of armor.