22nd Century Space Station
Notice I din't say "Starbase."
I have decided to begin work on a new Series using the CODA rules. The Series takes place on a Starfleet-built space station.
This is the first of mankind's truly extra-solar <i>Star Trek</i>-type space stations (as opposed to those like the International Space Station).
Designed by super-brilliant human engineers (with the assistance of Vulcan and possibly other alien engineers), the Starfleet space station is extremely dissimilar from the mushroom-shaped starbases of the 24th century. I envision a wheel-shaped station, slowly rotating in orbit (though not for the centrifugal force gravity-like effect... they have artificial gravity plating; I just thought it would look cool - and human).
The station itself is quite large, though nowhere near the size of a TNG or even a TOS starbase (i.e. not big enough to hold a starship inside). It is big enough that space vehicles (up to an including <i>Enterprise</i>-sized ships) are capable of docking with the station. I would say that it comfortably houses 150 full-time residents and could probably accomodate twice that number.
The station itself is not in Earth orbit but instead circles a colony planet (or an unihabited world) in a different star system (and I could sure use some help deciding which). I'm thinking that it would be in a strategically-important location, but not necessarily so. It is armed with pulse cannons and a compliment of torpedoes, but it is meant as a research facility and an "observation platform" outside of the Sol system.
I think that it will be equipped with some shuttles and some spacesuits for outside work (and I'm thinking like something along the lines of the outfit Carrie-Anne Moss used to save Val Kilmer in the otherwise unremarkable film <i>Red Planet</i>).
The PCs will be mostly human, but there will likely be a few aliens, particularly Vulcans. I also considered including an Andorian diplomatic envoy and/or perhaps a Risan or two.
While nominally a Starfleet installation, the station is more a place for humans to interact with alien cultures and explore the nature of the universe from a static location rather than on a starship.
Now, with all that written, this is not the first Starfleet space station. It is the first Starfleet space station beyond the Sol system. I'm thinking that they already have a space construction platform in Earth orbit and probably one in Mars orbit, too. Then there would be a Jovian space station, and probably a communications array (or something) out near Pluto. This new station, however, is state-of-the-art, incorporating some hard-won Vulcan technologies and other goodies.
[My premise for why the Vulcans donated manpower and technology is because they, as a race, do not build space stations, preferring instead to use planet-based facilities and starships alone. I've never seen or heard of a Vulcan space station, so that's why I decided this.]
The PCs are likely Starfleet officers (ensigns and junior grade lieutenants, for the most part) assigned to work on the station. One or more might instead be civilian specialists, alien "observers," or what have you. The station commander will be an NPC, as will the majority of the primary officers, but the PCs will likely have a lot of responsibilities and not a lot of resources at their disposal.
I'm thinking that this is set in the year 2163, a century after First Contact, and after a couple more Starfleet ships have been launched.
Now all I need is a name... and I don't care for Deep Space One! 
mactavish out.
Our country's past progress has been the result, not of the mass mind applying average intelligence to the problems of the day, but of the brilliance and dedication of wise individuals who applied their wisdom to advance the freedom and the material well-being of all of our people.
-Conscience of a Conservative, Barry Goldwater