This is one of the oldest games on the internet and a very fun text-based RPG! MUME is more than 30 years old and is still being actively developed, with new features and zones frequently added and a dedicated player base.
If you love Lord of the Rings, this is the closest you can get to an interactive version of the books, and has a massive world for you to explore full of familiar places like the Shire, Rivendell, Moria, Mirkwood and the Misty Mountains.