Hello there, I've been playing a MOO recently by the name of Star Conquest. It's a very interesting online game that enforces roleplay and is set some 300 years in the future. From the website itself:
Star Conquest is a pulp science fiction adventure RPG set 300 years in the future.
“Pulp” science fiction means that we went back to the sci-fi authors of the 50s and 60s, and built a future that they might’ve envisioned. Other solar systems are colonized, starships move faster than light through space, and there are aliens and strange artifacts to find.
Our game is also roleplay-intensive, and we encourage each player to develop a fleshed-out character concept.
Features:
Fully realized space system! Own your own starship, trade between distant spaceports, and explore the galaxy!
Full-featured battlesuit combat system! Fight on the ground against the enemies of humanity in your own suit of powered armor!
Event-driven storyline! Watch the game’s storyline unfold through regular events run by the staff! Influence the course of events!
Continually evolving game mechanics! An active staff improves game systems and creates entirely new ones continually!
Completely original! Our own original game design, our own code, and our own characters and story!
It's got a lot of interesting and original concepts. Players take the role of a new cadet fresh out of the academy from any of 4 different intergalactic empires (All based on things like military might, deep space exploration or manufacture and trade, etc) and are tasked with expanding and exploring in the name of the human race!
Player customization is extremely expansive, with a lot of different options not only at chargen, but also later in the game with features such as hair growth (not just on your head!), meaning that characters will have to go to the hair dressers on a regular basis if they don't enjoy that space-hobo look.
Ships are also massively customisable. Starting with a 1-man cruiser, you can deck it out with hundreds of objects ranging from one-use FTL drives to shag carpetting and waterbeds. Soon enough you'll be moving onto multiple man ships with their own crew compartments and gunning stations, meaning for some awesome team work opportunities whilst blasting away aliens in space combat.
There's also ground based exploration and combat, with lots of different planets to explore. I've only just started playing, and already I've met some wonderful people and been on some pretty cool adventures!
Check it out at:
http://web.squidsoft.net/games/sc/Hoping to see and roleplay with you guys ingame!
EDIT: Forgot to mention something about the playercount. I've seen around 50-60 people on at peak times ingame, which is pretty high for a mu* these days!